M i i Knnn i w i Mm wmn ii rinnmn i nH i rfi iii i itii n iiii i .i iii ikA^i^iMMiitt tMi^twtitttM *^ Wf > Mt i» y f ,«t^ HHfnTHmifT1M1fT||i||tt<i| 

THE ESSENTIALS OF 




THE NEW HEALTH SERIES 
SCHOOL PHYSIOLOGIES 




L. c 




Class 

Book.. : 

Copyright^ 

COPYRIGHT DEPOSIT. 



t 

o 



THE NEW HEALTH SERIES OF SCHOOL PHYSIOLOGIES 

THE ESSENTIALS OF HEALTH 

A TEXT-BOOK ON 

ANATOMY, PHYSIOLOGY, AND HYGIENE 

FOR USE IN 

HIGHER GRADES 

BY 
CHARLES H. STOWELL, M.D. 




SILVER, BURDETT AND COMPANY 

NEW YORK BOSTON CHICAGO 



LIBRARY of CONGRESS 
Two Copies Received 

MAK 20 1906 

ri/ . Copyright Entry 
CLASS OJ XXc. No, 
x COPY B. ' 






THE NEW HEALTH SERIES OF 
SCHOOL PHYSIOLOGIES 

A PEIMER OF HEALTH 

For Primary and Lower Grades. 

A HEALTHY BODY 

For Intermediate Grammar Grades. 

THE ESSENTIALS OF HEALTH 
For Higher Grades. 



Copyright, 1906, by 
SILVER, BUEDETT AND COMPANY 



PREFACE 

A sound mind in a sound body is the slogan of the 
twentieth century. In these days of intense activity one 
looks with admiration upon the man or woman with 
strong physique and vigorous intellect. The close rela- 
tion which exists between mind and body, and the influ- 
ence which the one is constantly exerting over the other, 
emphasize the necessity of the careful and thorough study 
of the essentials of health. 

Not many decades ago the beautiful woman was sup- 
posed to have pale cheeks and a languid manner and to 
lead an indoor life. But this anaemic style of beauty has 
been supplanted by the rosy-cheeked athletic girl who 
spends as much time as possible in the open air. Neither 
does the boy who has all brain and no brawn awaken 
within us a feeling of hearty approval; it is certain that 
he is greatly handicapped in the race for success. 

It was formerly thought that to obtain an education 
one had to risk vigor of health, but now it is known that 
mental labor is a real and a most important factor in our 
physical development. Indeed, it has been proved' time 
and again that young men and women who enter college 
delicate in health succeed not only in graduating with 
high honors, but in becoming, by careful regard of the 
laws of health, strong in body. 

It is the desire of the author to emphasize and explain 
more fully the importance of good health and its close 
connection with mental development. With this end in 



IV PREFACE 

view, the text of " The Essentials of Health " has been 
thoroughly revised, and its practical hygienic teaching 
has been greatly elaborated. 

Marked changes have also been made in the illustra- 
tions, many new ones being added, including four full- 
page diagrams in a new and original style and four color 
plates. 

This text complies in all respects with the requirements 
of the laws regarding the teaching of physiology and 
hygiene, with special reference to the effects of alcohol 
and other narcotics on the human body, as enacted by 
the several states. 

Lowell, Mass., 
March, 1906. 



CONTENTS 



Chapter - Page 

I. Cells 1 

II. Foods 8 

III. The Nitrogenous Foods 15 

IV. The Non-nitrogenous Foods 23 

V. Alcoholic Drinks .32 

VI. Digestion 39 

VII. Digestion in the Stomach and the Intestine . 51 

VIII. Absorption 62 

IX. The Blood . . . 71 

X. The Circulation 78 

XI. Respiration 94 

XII. Ventilation 108 

XIII. The Kidneys 119 

XIV. The Bones 122 

XV. The Skeleton . 130 

XVI. The Muscles 141 

XVII. Exercise 154 

XVIII. The Skin 101 

XIX. Bathing — Clothing 173 

XX. Animal Heat 180 

XXI. The Anatomy of the Nervous System . . 187 

XXII. The Physiology of the Nervous System . . 199 

XXIII. The Hygiene of the Nervous System . . . 208 

XXIV. The Sense of Sight 217 

XXV. The Senses of Taste and Smell .... 226 

XXVI. The Sense of Hearing 233 

v 



VI 



CONTENTS 



Chapter Page 

XXVII. The Senses of Touch; Temperature; Weight; 

Pressure; Common Sensation and Fain . 239 

XXVIII. Cigarette Smoking 244 

XXIX. Some Essentials of Health .... 253 

SUPPLEMENTARY CHAPTERS 

XXX. Emergencies 265 

XXXI. The Emergency Nurse . . . . . .283 

XXXII. Contagious Diseases 286 

INDEX 295 



THE ESSENTIALS OF HEALTH 



CHAPTER I 
CELLS 

Introductory. — We miss seeing many of the most inter- 
esting things that take place around us because they hap- 
pen so frequently that we pay little or no attention to 
them. Probably many of us never thought much of the 
lives of the horses and dogs and birds which we see every 
day until some "animal story" or some book of natural 
history opened our eyes. Then we found that there was 
much to be known about the animals, their bodies, how 
they live, what they do, etc. 

The human body is even more wonderful. What we 
now know about it men have studied hundreds and 
hundreds of years to learn, and indeed some remarkable 
discoveries have been made within comparatively recent 
years. There are practical reasons also for our wishing 
to know about our bodies and what they do, for upon the 
health of the body depends our ability to do our work 
comfortably and well. If we think it over we shall see, 
too, that the real success in life, which we are all ambitious 
to realize, must depend in part upon the ability of our 
bodies to do their work well and to carry out our wishes 
properly. The subject of our text, " The Essentials of 
Health," is therefore one of vital interest and importance 
to us all ; but before we consider what we can do to keep 

l 



2 THE ESSENTIALS OF HEALTH 

our bodies well and strong we must understand what they 
ought to do and how they ought to do it. Let us start 
with the smallest workers in the body. These are called 
the cells. Scientists have discovered that the whole body 
is composed of cells and of the products of their action. 
Each individual part of the body consists of cells quite 
characteristic in shape and size. By studying these cells, 
we learn much of the anatomy and physiology of the whole 
system. 

General Description. — Some cells are so minute that very 
high powers of the microscope are required to see them, 
while others are nearly large enough to be seen with the 
unaided eye. In shape, there is the greatest variation. 
There are spherical, oval, and spindle-shaped cells ; cells 
with branches extending in various directions, and still 
other cells with six equal sides. In color, there are the 
extremes from the black to the colorless, and from the 
brown to the yellowish green. There exists, therefore, a 
great difference in the shape, size, and color of cells. 

Structure of Cells. — Living cells consist of a transparent, 
jelly-like material, called protoplasm. The microscope 
shows that there are two parts to a cell : the body, or the 
greater part of the cell ; and the nucleus, or the smaller 
part in the center. The nucleus is usually spherical or 
oval, and, with few exceptions, is found in all cells. In 
rapidly growing cells, two or more nuclei are often found. 
The nucleus of a cell can be shown very clearly by the use 
of a carefully prepared solution of carmine. As the micro- 
scope shows, the carmine stains each nucleus bright red, 
but does not affect the body of the cell. 

The Life of a Cell. — It is probable that the great 
majority of cells are, comparatively speaking, short-lived. 
We must remember that the body is constantly and 



CELLS 3 

rapidly changing. Each movement of the body, each 
activity of a part, must cause a wear and waste of tissue ; 
and this loss must be replaced by new material within a 
short time. 

There are many ways of showing that the body is ever 
wasting away. If a drop of saliva be placed under the 
microscope, a vast number of thin cells can be seen. 
These cells come from the mucous membrane lining the 
mouth. The motion of the tongue, lips, and cheeks, as 
in speaking, eating, and drinking, removes vast numbers 
of these bodies. Then again, the surface of the whole 
body is covered with cells, many layers deep. The outer 
cells are easily removed by the friction of the clothing, 
and by the use of the sponge and the towel at the daily 
bath. In this way immense numbers of cells are being 
constantly destroyed, while new ones are as rapidly being 
formed beneath the surface to take their places. 

A more familiar example will illustrate this point. The 
finger nails are composed of cells so minute that a high 
power of the microscope is required to see them. Each 
paring of the nail, therefore, must remove vast numbers 
of these cells ; and yet, how rapidly even this hard struc- 
ture grows. Thus we learn that the body is ever chang- 
ing; the old, worn-out, and useless material being constantly 
cast off, and the new as regularly taking its place. 

Some cells are much longer lived than others. It is 
probable that the cells found in such hard tissues as bone 
and cartilage undergo comparatively slow changes, while 
the cells in some of the glands change with great rapidity. 
In fact, the whole life history of a cell in some of the most 
active glands may be covered by a few hours. 

Growth and Development. — Cells increase both in size 
and number. After reaching certain dimensions, however, 



4 THE ESSENTIALS OF HEALTH 

they cease to grow. They may then either maintain that 
size for the remainder of their life, or they may, by a 
peculiar process of division, become temporarily smaller. 
This process is called cell division. When a cell is about 
to divide, its nucleus becomes constricted in the center, 
assuming a dumb-bell shape. This constriction increases 
until the nucleus becomes divided into two nuclei. The 
body of the cell then undergoes the same change in form 
until it has divided into two cells, with one nucleus for 
each cell. A process, or bud, protruding from the body 




Fig. 1. —Diagram illustrating the divisions of cells: (1, 2, 3, 4, 5) by 
cell division ; (6, 7, 8) by budding. 

of a cell is still another method of division. Soon this 
process separates from the original cell, and a nucleus is 
developed within it (Fig. 1). 

Some Cells have Motion. — The great majority of the 
cells in the body are fixed and cannot alter their shape 
or position. There are some, however, that not only have 
the power to change their shape, but also to move from 
place to place. These movements are known as the 
" amoeboid movements,' 9 so named from a very minute 
animal called the amoeba (Fig. 2). 

The amoeba is usually regarded as the lowest form of 
animal life. It is of jelly-like consistence, and averages 
from -g-i-Q to 2 ^ of an inch in diameter. It is found in 
stagnant water, and in water in which there is decaying 
animal matter. The amoeba is an object of intense interest 



CELLS 



to all physiologists, because it represents not only a single 
cell but also a whole individual. It is remarkable for its 
constant and rapid changes of form, causing it to move 
about in any direction. As already stated, the amoeba is 




Fig. 2. — Various forms assumed by an amoeba. These sketches were 
made from the same amoeba, at intervals of a few seconds. 

an animal, the lowest in the scale ; yet it moves ; it takes 
nourishment ; it reproduces its own kind ; and it dies. 

The Function of Cells. — Each cell in the human body 
can take material brought to it by the blood and change 
that material into its own structure. To illustrate : the 
cells of the salivary glands can take digested food from 
the blood and change it into the tissue of the salivary 
glands ; the cells of muscle can take something from the 
blood and build from it true muscular tissue ; the cells of 
the skin can take nourishment from the blood and make 
from it the soft covering for the body. Thus, while a 
person may eat only one kind of tissue-building food, it 
is possible for this food to be changed into all the various 
structures of the body. 

But the cell can do even more than this ; it can take 
material from the blood and change it into a substance 
unlike its own. For instance, a cell in the salivary glands 
can take material brought to it by the blood and change 
it into saliva ; cells in the glands of the stomach can 
take material from the blood and change it into gastric 
juice. 



6 THE ESSENTIALS OF HEALTH 

Composition of the Body. — Water forms a large part of 
the weight of the body, and there is also considerable fat. 
We all know that some persons have less flesh than others, 
but the body always contains fats ; even after long-con- 
tinued illness there is always some fat still remaining. 
Proteid, which we see in one of its forms in the white of 
the egg^ forms a large part of the solid tissues of the body ; 
and it is also found in some of the fluids of the body. 
There is also some mineral matter in the body, principally 
lime, soda, and potash ; there is also some iron, and there 
are traces of other minerals. 

Effect of Alcohol upon the Cells. — As the strength of a 
chain depends upon the strength of its individual links, 
so the health of the body depends upon the health and the 
perfect working condition of its cells. The cells of the 
body are bathed with blood and consequently are affected 
by whatever the blood brings to them. The effect of 
various substances upon cells similar to the cells of the 
body has been watched through the microscope. One 
observer reports that when a living cell was bathed in a 
liquid containing a meat extract, it expanded, made more 
lively movements, and appeared to be benefited. When 
the cell was bathed in an astringent substance, such as 
tea, it contracted, became nearly or quite motionless and 
remained so until again bathed in a nutritive substance, 
when it revived. But if the cell was bathed in alcohol or 
an alcoholic solution, it contracted, remained motionless, 
and could not again be revived. It was dead. 

The alcohol that reaches the cells of the body after an 
alcoholic drink is taken is usually too much diluted to kill 
the cells, but it can and often does impair their vitality 
for a longer or shorter time, in proportion to the amount 
of alcohol that reaches them. A recent writer on this 



CELLS 7 

subject -(Dr. Overton, of Zurich) states that while the 
outer membrane of a cell is able to keep many injurious 
substances from penetrating within, it cannot prevent 
ether, chloroform, alcohol, and other substances of that 
class from coming into contact with it and injuriously 
affecting its substance. The more delicate the cell, the 
more easily and seriously it is harmed. 



CHAPTER II 
FOODS 

Waste and Repair. — Every activity of the body, con- 
scious or unconscious, is followed by a waste of material. 
And since some part of the body is always in motion, it 
follows that the body is always wasting away, and thus 
should be constantly undergoing repair. The processes of 
waste and repair do not always bear the same relation to 
each other. 

Early in life, the building up greatly exceeds the break- 
ing down ; more material is supplied than is worn out 
and removed ; the processes of repair exceed those of 
waste, and the body grows and develops. Later in life, 
the repair and waste are nearly balanced, and for a 
number of. years the form and weight remain about the 
same. As old age conies on, the weight diminishes and 
all the forces of the body become less active. The waste 
now exceeds the repair. 

From the food that we eat, the body must obtain the 
materials for building its structure and for keeping it in 
repair. 

Oxidation and Energy. — Besides building material, the 
body needs material that will furnish force, or energy, 
for carrying on its various functions. 

When a building is being erected, machinery is gener- 
ally used to lift the heavy stones and swing them into 
place. An engine puffing and panting on the ground 

8 



FOODS 9 

furnishes the force, or energy, with which to do this, and 
the energy is obtained from the burning of coal or of wood 
in the engine. 

As the burning of the coal in the engine sets free the 
energy stored up in the coal, so the burning of the food 
in the body sets free the energy in the food, which warms 
the body and enables it to work. 

The principal elements which go to make up our foods 
are carbon, oxygen, hydrogen, and nitrogen. These exist 
all about us, in the earth and in the air, and generally in 
a free state, but in this form they do not nourish us, are 
not really food for us. The growing plant, however, can 
take up these simple elements and build its own structure 
from them. To illustrate : the growing rice plant takes up 
(from the soil, the water, and the air), carbon, oxygen, and 
hydrogen, and so unites or combines them as to increase 
and build up its own substance. The same is true of 
growing wheat, only in this case the plant takes up nitro- 
gen, in addition to the carbon, oxygen, and hydrogen. 

In order to do all this building up the plant requires 
force, and this force it derives from the sun. It is sun- 
light. This sunlight, or energy, will remain stored up in 
the rice or the wheat until these elements, carbon, hydro- 
gen, oxygen, etc., are broken apart, or disintegrated. 
Then the stored energy will be set free, and will be used 
as heat for the body or strength for muscle. 

The process by which food is broken up or burned in 
the body and transformed into energy is called oxidation. 

An animal body may use as a source of energy, either 
vegetable structures or other animal structures. Whatever 
living substances an animal body can digest and absorb 
within itself, will yield to it a corresponding amount of 
energy. Man cannot obtain energy from hay, because his 



10 THE ESSENTIALS OF HEALTH 

digestive processes are not capable of reducing hay to a 
state in which it can be absorbed. We do not therefore 
call hay a proper food for man ; we do call it food for the 
cow and horse, because they are capable of digesting and 
obtaining energy from it. 

Not every substance which can be absorbed and oxidized 
in the animal body can properly be called a food for that 
body. There are substances, for instance, which although 
irritating to the animal tissues can be oxidized into simpler 
and less injurious substances, if only small amounts are 
present. Such substances may yield, it is true, a certain 
amount of energy as they are broken up, but the amount 
of energy is overbalanced by the injury the body receives 
from being badly poisoned. It is little short of absurd, 
then, to speak of such substances as foods. Carbolic acid 
and alcohol may be oxidized in the body and so yield 
energy, but their chief effect is to poison the tissues, and 
hence they are not classed as foods, but as poisons. 

Foods and poisons are thus distinguished by accepted 
definitions : — 

A food is any substance whose nature it is, when 
absorbed into the blood, to build up the body or to furnish 
it with energy for work or for warmth, without injuring it. 

A poison is any substance whose nature it is, when 
absorbed into the blood, to injure health or destroy life. 

Classification of Foods. — All three of nature's kingdoms 
are called upon to furnish articles of food. The princi- 
pal articles obtained from the mineral kingdom are water 
and salt ; from the vegetable kingdom, such cereals as 
wheat, corn, and oats, and a large number of vegetables 
and fruits ; from the animal kingdom, various meats, 
milk, and eggs. 

For purposes of study, foods are divided into the organic 



FOODS 11 

and inorganic. The organic foods are obtained from liv- 
ing substances, or from things which once had life. The 
inorganic foods are derived from inorganic substances, such 
as earth and water. 

The Inorganic Foods 

The two principal inorganic foods are water and salt. 
These are found in many forms of food and are also added 
to the food in cooking. 

Salt. — Salt is found in all the tissues and organs of the 
body, except in the enamel of the teeth. It is estimated 
that there is nearly one quarter of a pound of salt in the 
entire body. In a small amount, salt is present in nearly 
all the organic foods in use, but not in sufficient quantity 
to meet the demands of the system. That salt is a 
necessary food is indicated by the natural craving for it, 
not only in man, but in the lower animals as well. Wild 
animals on the hills and prairies will travel many miles in 
search of salt ; while the domestic animals, like cattle and 
sheep, will come quickly to the farmer's call, expecting 
some of this necessary food. Such animals as sheep and 
cows, which live chiefly upon the grasses, fail to obtain a 
sufficient supply of salt with their food ; those animals 
living principally upon meats receive all that they need, 
as saU is already in the meat itself. Such animals may 
even have a repugnance for salted meats. 

Salt gives a flavor to the food and stimulates the appe- 
tite. Food may be very nutritious, yet if it be tasteless 
it is not eaten readily, and is digested with difficulty. 

Water. — Water constitutes nearly three fourths of the 
weight of the entire body. It is universally present in 
all the tissues and fluids of the body. There are many 
reasons why water is so important. All the food that 



12 THE ESSENTIALS OF HEALTH 

we eat must be dissolved before it can be digested. 
Therefore water is the most important substance used 
for food, as it is the one universal solvent. The water in 
the tissues holds in solution numerous substances, both 
the foods and some of the waste materials of the body. 
Through the blood and tissues water becomes a circulat- 
ing medium for conveying the foods held in solution to all 
parts of the body, and for taking away from the tissues 
the worn-out and useless ingredients. 

Water gives elasticity to the bones, the muscles, the 
tendons, and the other tissues. The craving for water is 
greater than for any other food, and if deprived of it, a 
person will die sooner than if deprived of solid food. 

A large quantity of water is taken into the system dur- 
ing each day. Some of this is taken purposely, as a drink, 
while a large amount is taken unconsciously with the food. 
To prove the truth of this latter statement, we have only 
to remember that one half the weight of beef, three fourths 
the weight of potatoes, and nine tenths the weight of milk, 
consists of water. A healthy man takes, on an average, 
about two quarts of water each day. 

Sources of Water. — Rain water most closely resembles 
distilled, or chemically pure water. It usually contains a 
small amount of carbon dioxide. Spring water contains 
a considerable amount of mineral substances and carbon 
dioxide, the latter giving to spring water its fresh taste 
and aiding in dissolving the mineral substances as the 
water permeates the soil. Spring water contains but 
little oxygen ; therefore, many vegetable organisms are 
usually found in it, while animal life, which requires much 
oxygen, is poorly represented. Spring water may bubble ■ 
to the surface of the earth, or it may be brought within 
reach by some mechanical device such as a pump. 



FOODS 13 

The Purity of Drinking Water. — Drinking water should 
be colorless and without the slightest odor. Chemically 
pure water, however, is not pleasant to the taste ; it lacks 
the snap and tartness of spring water. Then, too, the 
presence of some minerals in solution is useful to the 
system. Lime is important, for instance, in the forma- 
tion of teeth and bone, and drinking water which contains 
lime, if it is not present in excessive quantities, must be 
regarded as healthful, especially in early life, when the 
tissues are developing. 

On the other hand, lead is a very dangerous ingredient 
of water. Water that has stood in lead pipes should 
never be used for drinking purposes. If it is necessary 
to use lead pipes, then the water should be kept running, 
or a large quantity should be drawn off before any is used. 
There is no reason for supposing, simply because water 
has no odor and looks clear, that it does not contain in 
solution substances of a most poisonous nature. 

Organic matter in a state of decomposition may be 
present in water. When there is any danger of this, it 
is much better to boil the water for ten or fifteen minutes, 
and thereby destroy the minute germs. During an epi- 
demic of typhoid fever, it is a wise precaution to drink 
no water that has not been boiled. 

Other Inorganic Foods. — There are other inorganic foods, 
besides water and salt, such as the various chemical salts, 
including the salts of soda, potash, and lime. 

The Organic Foods 

The organic foods are derived from the animal and the 
vegetable kingdoms. For convenience they are usually 
divided into two classes, called the nitrogenous and the 



14 THE ESSENTIALS OF HEALTH 

non-nitrogenous foods. We shall understand the reason 
for making this division when we remember that nitrogen 
is the basis of all tissue-forming food ; that is, by the 
nitrogen in our food the tissues of the body are built up 
and are kept in repair. Without nitrogen the boy would 
not grow and the man would not be able to repair the 
tissues of the body, which are constantly breaking down 
as we work. We see, therefore, that the foods which we 
have classified as nitrogenous might also be classified as 
the building and repairing foods. 

The non-nitrogenous foods are equally necessary to the 
health of the body, for they are the foods that enable the 
body which has been built up by the tissue-forming foods 
to perform its work. They are sometimes called the fuel 
foods ; and we have already learned that they are oxidized 
in the body. It is true also that the proteids may be 
used, to a greater or less extent, as fuel foods, if the 
body needs extra fuel. 

When we begin to classify foods in this way, we must, 
however, remember that one article of food often contains 
many different food substances, and so will properly fall 
into several different food divisions. Take, for instance, 
wheat bread as it is usually made. We think of it as a 
very simple food, but it contains tissue-making material 
(proteid) and also fuel materials, such as starch, besides 
much water, which we have learned to be an inorganic 
food, and some salts. So while, for convenience, we shall 
proceed to take up the foods we naturally eat, placing 
them in the usual divisions, we should remember that 
this classification is for convenience and is not complete 
or exclusive. 



CHAPTER III 
THE NITROGENOUS FOODS 

The Proteids. — The nitrogenous foods are generally 
called proteids. They include such foods as the lean 
meats, eggs, and milk. There are four forms of proteids 
which we find commonly eaten. It is not important to 
distinguish between the action of each in the body, but it 
may be of interest to name them. They are, (1) albumen, 
which is found in its purest form in the white of the egg ; 
(2) myosin, the lean part of meat ; (3) gluten, found 
in cereals ; and (4) casein, the thick white substance, or 
curd of milk. A diet cannot be nutritious that does not 
contain the proper proportion of proteid food. 

We have spoken of the importance of proteids as the 
foods required to build and to repair the body. Scientists 
who have studied the body tell us that proteids form the 
chief part of the muscles of the body and are present in 
nearly all its fluids. This being the case we can see that 
the body, if kept in health, must be supplied with ingre- 
dients that are found in its tissues. This does not mean, 
however, that we should eat chiefly proteids. There are 
nations, notably the Chinese, in which the poorer people 
probably do not eat a sufficient quantity of proteids, but 
scientists tell us that in this country, as most of us live, 
we more often take too much proteid than too little.. It 
used to be the popular impression that in order to do 
good work the body needed a great deal of meat. Experi- 

15 



16 



THE ESSENTIALS OF HEALTH 



ments have shown, however, that the necessary proteids 
can be secured from eggs and from cereals as well as from 
meat. Many people find that they can to advantage cut 
down the amount of meat usually consumed per day. 

Milk. — The " model food" is the name often given to 
milk ; and it is true that no food can suruass it. Since it 
contains all the necessary food elements, it will support 

life longer than 
any other single 
article of diet. 
It must, how- 
ever, be taken 
in larger quan- 
tities than the 
other proteids, 
for it contains 
a large amount 
of w T ater, nearly 
nine parts in 
ten ; it has 
a considerable 
amount of fat, 
most often used 
in the form of 
butter; a sugar, known as milk sugar; minerals; and pro- 
teids. The mineral matter consists largely of lime, so es- 
sential to the formation of the bones when they are growing. 
The nitrogenous matter in milk consists almost entirely 
of albumen and casein. If any acid be added to milk, 
the casein is thrown down in a coagulated form, and the 
milk is said to be curdled. The milk curdles without the 
addition of an acid if it is exposed to the air for a few 
hours in a warm room. This is because of the develop- 




Fig. 3. — Milk, highly magnified. 



THE NITROGENOUS FOODS 



17 



ment of lactic acid in the milk. The action is the same 
as if the acid were added intentionally, and the casein 
thus coagulated. From this coagulated mass, or curd, 
cheese is made. The fat of milk consists of vast numbers 
of minute oil drops. Under the microscope, these appear 
as small round globules floating in water (Fig. 3). 

Milk should be the principal food of children, while 
for adults it may be used as a drink with the ordinary 
meals. Warm milk may take the place of a cup of coffee ; 
cold milk is a good substitute for ice water. Some people 




An outdoor milking scene on a model dairy farm. 



claim that they cannot use milk, as it disagrees with the 
stomach and interferes with the action of the liver. These 
troubles are easily prevented by using only a moderate 
amount, and by adding to it a dessertspoonful of lime 
water to a glass of milk. 

Care of Milk. — It used to rest with the farmer or the 
dairyman to see that the milk he offered for sale was 
clean and pure. People came, however, to appreciate the 
great importance of the purity of the milk they used. 
They learned that milk very readily absorbs gases and 



18 



THE ESSENTIALS OF HEALTH 



impurities of various kinds, and further, that it may also 
be the means of communicating disease, either from being 
adulterated with impure water, or from having absorbed 
injurious gases or other impurities. Care is all the more 
necessary as we use a great deal of milk without cooking 
it, — a process which would destroy any harmful germs. 
Consequently much attention has been given of late to 
the proper care of milk, and in many places there are 
laws forbidding the sale of milk that does not reach a 




Interior of the milking honse of a dairy farm. (The cows are never milked 
in the harn where they are stabled.) 



certain standard of richness and purity. Such super- 
vision of our milk supply has resulted in special attention 
to every important detail, such as the care of the cows, 
the cleanliness of the barns in which they are stabled 
and the places in which they are milked, absolute cleanli- 
ness on the part of the milker and in the handling of 
the milk. In many dairy farms all these matters are 
now arranged in a most careful and scientific manner. 
The illustration on page 17 and the one above* show two 
actual milking scenes at a model dairy. 



THE NITROGENOUS FOODS 19 

Care, however, cannot cease when the milk is delivered 
in perfect condition to the consumer. It must be kept cold, 
and in a room or ice-chest that is absolutely clean and 
free from odors. It is a safe precaution, when one is not 
sure of the purity of the milk used, to scald it as soon as 
it is received ; that is, heat it to the boiling point, but do 
not boil it. Then cool it quickly and place in the ice- 
chest, covered. Milk dishes should always be scalded 
before they are used. Any germs that get into milk 
develop quickly during the heat of the summer months, 
producing severe stomach and bowel diseases, and caus- 
ing very many deaths among young children. As these 
germs multiply and grow more rapidly when the milk is 
warm, great care should be used to put it in a cool place 
as soon as it is received and to keep it cool. It ought to 
be kept in a refrigerator. 

As the refrigerator is a place for keeping food it should 
always be as clean as it can possibly be made. All the 
food should be in dishes or receptacles of some kind. No 
crumbs or particles of food should ever be allowed to 
remain on the shelves. At least once a week the refrig- 
erator should be thoroughly washed with hot water. The 
importance of this — especially when there are children 
in the house who depend upon milk for a diet — can hardly 
be overestimated. Keep the refrigerator spotlessly clean. 

Eggs. — Eggs are easily digested and very nutritious. 
They are most digestible when soft-boiled in the shell, or 
when broken into boiling water. The principal differ- 
ences between the white and the yolk of the egg are 
these : the white contains no fat, the yolk is about one 
third fat; the white contains albumen and a large per- 
centage of water, the yolk contains no albumen, and only 
about half as much water as the white. 



20 THE ESSENTIALS OF HEALTH 

Meats. — The meats used for food are rich in nitroge- 
nous ingredients, together with fat and mineral matter. 
The meats differ in their digestibility and in their nutri- 
tive value. Beef is regarded as the best meat for general 
use. When tender beef is properly cooked, it is easily 
digested and very nutritious. Mutton ranks next to beef. 

Veal is not easily digested, neither is it so nourishing 
as beef and mutton. Pork is not readily digested ; the 
fibers of the lean meat are too compact, and the fat is 
likely to be in excess. A large class of people, however, 
eat it freely. To those who exercise much, and those 
who have strong digestive powers, pork appears to do no 
harm. Oysters contain only a small proportion of nour- 
ishment, but they are easily digested, when eaten raw, 
and are very pleasant to those who have acquired a taste 
for them. 

The Cereals. — The cereals, comprising chiefly wdieat, 
oats, corn, and rice, are most important foods. They 
consist of nitrogenous material, starch, sugar, salts, and 
fat. The starch is seen as the white center of the grain, 
surrounded by a husk. The husk consists of a woody 
material and is quite indigestible. The nitrogenous por- 
tion of the grain is situated between the husk and the 
starchy center. Wheat flour would be much more nutri- 
tious if only the husk, or bran, were removed, and the 
layer containing the nitrogenous matter and the gluten, 
oil, and salts retained with the starch. The flour and the 
bread made from it would not be so white, but would be 
more wholesome. The gluten, which gives the adhesive, 
jelly-like quality to the cereals, is very abundant in wheat, 
forming about twenty per cent of the whole grain. 

The grains vary in their proportions of nitrogen and 
starch ; but their value as a food does not depend alone 



THE NITROGENOUS FOODS 21 

upon the amount they contain of any single nutritive 
ingredient. There should be such a variety of substances 
as will form the best combination for the nourishment of 
the body. 

Wheat excels all the cereals in nutritive value. It 
is easily digested and, with the exception of milk, it 
comes nearest to the standard of a perfect food. It is 
well supplied with nitrogenous material ; contains but 
a small proportion of water ; has a large amount of 
starch ; and also considerable mineral matter and some fat. 
There is, however, a deficiency in the amount of fat it 
contains ; therefore this must be supplied by putting 
butter on the bread. The proportion of water is so small 
that a given bulk of wheat is richer in solids than any 
other food. Probably the best test for a good wheat is 
the kind of bread it will make. 

Oatmeal contains a large amount of nitrogenous mate- 
rial, ranking in this regard nearly or quite equal with 
wheat ; but it contains also a considerable amount of 
woody or fibrous material, which interferes with the 
digestion of it and lowers its nutritive value. Since it 
lacks adhesive qualities, it cannot be made into bread. 
Yet it is a wholesome food, and to most persons 
agreeable. 

Corn contains less nitrogenous material than oats, but 
it has more starch. Rice consists of ninety per cent of 
starch with scarcely any nitrogenous material. When 
taken with some proteid, such as meat of any kind, it 
is a valuable article of diet ; it is easily digested and is 
also very cheap. 

Vegetables. — Peas and beans are very nutritious, since 
they contain a good amount of proteid and of starch. They 
consist of such solid matter, however, that they are not 



22 THE ESSENTIALS OF HEALTH 

easily digested. When used, they should be cooked a 
long time, and should be thoroughly masticated. 

Potatoes consist of from seventy to eighty per cent of 
water ; the remainder being nearly all starch, together 
with a small amount of mineral matter, proteid, and 
salts. Although they consist so largely of water, yet they 
are the most generally used of all vegetables. This is 
because they can be obtained at all seasons of the year, 
are very cheap, and agree with most persons. They 
should never form the exclusive diet ; but, when used 
with some fat, as butter or meat gravy, and with salt, to- 
gether with some food rich in nitrogenous matter, they 
form a most valuable adjunct to the table. 

Turnips, cabbage, parsnips, onions, and other vegeta- 
bles are added to the list of foods in order to give suit- 
able variety. Their nutritive value is low, and they are 
not easily digested. 

Fruits. — ■ Apples, peaches, pears, and other fruits are 
valuable foods in many ways. They contain a considerable 
amount of sugar and of mineral matter, while their acids 
give each its characteristic taste. These acids serve to 
stimulate the appetite and promote the flow of gastric 
juice, while the great amount of water they contain serves 
to quench the thirst. Ripe fruits in their season are most 
beneficial ; overripe and unripe fruits, on the other hand, 
are often the cause of serious trouble. Much of the danger 
of unripe fruits can be removed by cooking. 



CHAPTER IV 
THE NON-NITROGENOUS FOODS 

The non-nitrogenous foods consist of starch, sugar, and 
the fats. They are, as already stated, the fuel foods. 
There is a natural craving in the body for these foods, 
and experiments have proved that they cannot be dispensed 
with for any great length of time without serious injury 
to the health. This seems to be especially true when the 
body is growing rapidly. 

Fats. — Some individuals do not digest the fat of meats 
readily, yet they can use butter and milk. Others are 
able to digest such fatty foods as bacon, or the fat of 
other meats. Fat has great heat-producing power, there- 
fore it is most used where the climate is cold and severe. 
Many children who are given enough food to eat suffer 
from what we might call " fat-starvation.*' Perhaps they 
have a foolish dislike of fat, or it may be that their parents 
do not realize that an active child needs much fuel food, 
to maintain all his natural activity. 

It is probable that some of the fat in the body is 
derived directly from the fat of the food ; that is, the fat 
is digested, absorbed and deposited in the tissues. But 
it is equally true that fat may be formed in the body 
from foods which are without fat. This is proved to be 
a fact with animals, because the amount of fat, or butter, 
found in the milk of the cow far exceeds the amount of fat 
taken as food. 

23 



24 



THE ESSENTIALS OF HEALTH 



It is true, too, that some persons become very fleshy, while 
others, with the same diet, remain lean. In many fami- 
lies there is an inherited tendency to grow fleshy. It 
is probable also that, in some cases at least, more food 
is taken than is necessary for the normal uses of the 
body. A deposit of too much fat is attended with incon- 
venience and frequently with danger. 

Starch. — Pure starch is a fine, white powder, consist- 
ing of minute granules. When examined under the 
microscope, the granules are seen to vary in size and form, 




Fig. 4. — Starch grains : (1) from the potato, — potato starch grains ; (2) from 
wheat, — wheat starch grains ; (3) from oat, — oat starch grains. 

according to the kind of starch. Thus, by the appearance 
of the granules, it becomes possible to tell from what vege- 
table the starch was obtained. The three illustrations 
given (Fig. 4) show these marked differences. Each kind 
of starch is magnified the same number of times, or about 
five hundred diameters. The granules are very minute, 
those of rice starch being not over g-^Vo °^ an i nc h in 
diameter. When mixed with water, the granules swell 
and form a paste ; when boiled with a large amount of 
water, they expand greatly, and can no longer be seen. 
The destruction of these granules is a great aid to their 
digestion. Prolonged cooking changes the starch into 
a substance called dextrin. This is easily transformed 
by the digestive juices in the body into grape sugar. 



THE NON-NITROGENOUS FOODS 25 

The brown crust of the bread is the starch of the flour 
changed into dextrin by the prolonged exposure to 
heat, hence it is more easily digested than the softer 
parts of the bread. In order that the starch granules 
may be completely broken up, all starchy foods should be 
thoroughly cooked. A too exclusive diet of starchy foods 
is likely to impair the digestive powers ; for the digestive 
juices are unable to change promptly large quantities 
of starch into sugar, and consequently the sugar is slowly 
absorbed if it is present in too large quantities. This gives 
rise to the formation of gases and acids, and dyspepsia 
then follows. 

Sugar. — Sugar is closely allied to starch, both in its 
chemical and physiological relations. In the living plant, 
the sugar and the starch represent the same nutritive 
material, though under different conditions ; the sugar 
is in the form of a liquid, and the starch is in the form 
of a solid. 

There are three principal varieties of sugar, — cane 
sugar, grape sugar, and milk sugar. Cane sugar is ob- 
tained from the juice of the sugar cane. It is the varietj^ 
in ordinary use. It is made also from the juice of the 
maple tree, and is called maple sugar. It is the most 
soluble and the sweetest of the sugars. Grape sugar 
is found in great abundance in the juice of ripe grapes. 
It is generally distributed in the sweet juices of many 
fruits and flowers. This is the reason it is found in 
honey, although cane sugar is also present. Grape sugar 
is found in some of the animal tissues and fluids, as in 
the liver and the blood. This is the form of sugar which 
is made in the body by the digestion of starch. The 
third variety, the sugar of milk, is found only in milk. 
Its sweet taste is not very marked. 



26 THE ESSENTIALS OF HEALTH 

While it is true that a considerable quantity of sugar 
is likely to disturb the stomach, yet it is equally true 
that a certain amount is very desirable. The natural 
desire for sweet things is universal and it is based on 
a demand of the system for this food. Appetite is not 
always a safe guide, however, when the taste of a food, 
like that of sugar, is so agreeable. If boys and girls eat a 
little less sugar than they desire they will be on the safe 
side. If candies are desired, eat only those made from 
pure sugar ; but it is better to try to satisfy the craving 
by eating ripe fruit. There is no danger that the teeth 
will be injured by the use of sweet foods, if they are 
cleansed after eating, as should always be done. 

Bread. — Bread is often called the staff of life, because 
it contains so many nutritious elements, being deficient 
only in fat. Thus it follows that bread and butter 
make a very complete diet. 

In making bread, the flour is mixed with water until a 
dough is formed. Salt and yeast are then added. The 
dough is set aside in a warm place until fermentation is 
well established. In the process of fermentation, the 
nitrogenous ingredients begin to decompose and act as 
a ferment on the starch, which becomes, in part at least, 
changed to sugar. The sugar is further decomposed into 
carbon dioxide and alcohol. The carbon dioxide forms 
bubbles ; these force their way through the dough, or 
sponge, making the bread rise. The dough is now placed 
in an oven hot enough to stop fermentation at once. 
The alcohol is all driven off by the heat, and much of the 
water also. The bread is then said to be baked. 

Yeast, however, is not essential to the making of bread. 
Unfermented bread is made by mixing with the dough a 
powder composed of an acid and an alkali, so that after 



THE NON-NITROQENOU& FOODS 27 

the powder is moistened in the bread, the acid and the 
alkali form a new compound, and carbon dioxide is set 
free. 

In aerated bread, the carbon dioxide is forced into 
water and the flour then mixed with this water under 
pressure. When the dough is heated, the carbon dioxide 
expands and makes the bread spongy. 

Bread made from unbolted flour is very nourishing, 
as it contains all the gluten of the wheat, but the presence 
of the bran makes it difficult to digest, so that it should 
not be used by persons with weak digestive powers. 
Hot bread is likely to form a paste in the mouth, and 
as the digestive juices cannot then work on it readily 
its digestion becomes difficult. 

The Amount and Kind of Food. — No rule can be laid 
down saying positively just how much of each kind of 
food must be taken ; but if the body be in a healthy con- 
dition, an amount should be taken sufficient to satisfy the 
appetite. The appetite, however, is not always a safe 
guide, because by irregular habits, by overeating, and by 
eating improper articles of food, it becomes variable, and 
is then an unreliable test. If persons would form the 
habit of eating a regular diet of plain, wholesome food, 
there would be far less dyspepsia with its attending dis- 
turbances of the nervous system. 

The quantity of food must vary with the amount and 
kind of exercise. A good rule is this : Learn which 
foods are wholesome, and how they should be cooked ; 
then watch yourself for a time, and decide what and how 
much it is wise for you to eat. Some persons require 
only a small amount of food to keep them in good 
health, while others require much more. This is partly 
because one person uses up more energy than another ; 



28 THE ESSENTIALS OF HEALTH 

it may be in work, in exercise, or in worry. Another 
difference is in the proportion of the food taken that is 
assimilated by different persons; for after all it is not 
the amount of food we eat, but the amount digested and 
taken up by the body that determines whether we are 
overfed or underfed. Sickness is caused by overeating, 
as well as by eating things which are harmful. Remember 
that a mixed diet is better. Habit and custom have 
altogether too much to do with determining the kind and 
amount of food that people eat. 

Cooking. — It is necessary to cook most kinds of food, in 
order that they may be properly digested. Oysters and 
certain ripe fruits are the principal exceptions to this 
rule. Cooking coagulates the albumen in the foods ; 
it renders the fatty tissues more fluid ; it changes the 
starchy foods into a pulpy mass, and it breaks up the 
harder tissues of the vegetables. Thus the foods are 
softened, and are more easily masticated. Cooking also 
brings out distinct and agreeable flavors in foods. 

Methods of Cooking. — In broiling, roasting, or boiling 
meat, it is desirable to retain in the meat as much of the 
nutritive properties as possible. This can be done by 
applying great heat at first, which produces a rapid coagu- 
lation of the albumen on the surface, thus forming a 
crust, through which the nutritive juices of the meat can- 
not escape. Afterward the cooking should proceed with 
a less degree of heat, until the meat is cooked to please 
the taste. 

When meats are cooked too thoroughly, their natural 
juices are driven off by the prolonged heat, and their 
albuminous matter is rendered hard and dry. Such 
meats are masticated with difficulty and digested slowly, 
while much that is nutritious is lost. 



THE NON-NITROGENOUS FOODS 29 

Broiling is the best method of cooking meat ; roasting 
is nearly as good. Vegetables and the coarser meats 
can be made very tender by prolonged boiling; remem- 
ber that they should be placed at once in boiling water, 
and then allowed to cook slowly in water that is kept 
barely above the boiling point. 

When we are studying about the best foods and how 
they should be cooked, we must not overlook the real 
reason why these matters are so important. That is 
because, within certain rather variable limits, the body 
can manufacture, day after clay, only about so much 
energy or force. If we choose our food so badly that 
an extra amount of energy is needed for the work of 
the digestion '(about which we shall learn more later), 
then there is so much less energy for other work that 
we want to do. When there is so much good, digestible 
food to be had, it is foolish to make our bodies waste 
their energy on food that is indigestible in itself or is 
made so by being cooked improperly. 

Frying is the least desirable of all the methods of pre- 
paring meats and other foods ; in fact, it is an actually 
injurious method. The fat in the meat, or the fat in the 
frying pan, penetrates the lean portions of the meat and 
surrounds each particle with a layer of oil. As oil is not 
digested in the stomach, it follows that the meat with its 
oily covering must pass out of the stomach before the 
outer coat of oil can be completely removed. Certain 
fatty acids which are likely to prove injurious also are 
developed during the frying process. When food must be 
fried, the fat should be boiling hot when the articles are 
put into it, and it should be kept boiling during the entire 
cooking. Thus by forming a hard outer coat at once, the 
fat is not so likely to penetrate deeply. 



30 THE ESSENTIALS OF HEALTH 

In making soups, it is better that all the juices be 
extracted from the meat, — a result just the opposite of 
the one desired in broiling or roasting. Therefore the 
meat should be cut into small pieces and placed in cold 
water at first, the water being allowed to come gradually 
to a high temperature. In this way no layer of coagu- 
lated albumen is formed on the outside, and all the juices 
are brought out by the water. 

Economy of Food. — There is much that might be said 
about the economy of food that cannot find a place here, 
but every one who cooks ought to study that problem 
carefully. Many times, however, the importance of 
absolute cleanliness in the preparation and care of food 
is not appreciated. As the kitchen is the place where 
food is prepared for the table, everything in it should be 
clean and neat. Stoves should be kept polished; all the 
cooking utensils should be models of neatness ; the broom 
and the mop should be frequently called into use, and 
none of the refuse from preparing the meats and 
vegetables should be allowed to stand in the room for 
any length of time. The one who does the cooking 
should, of course, always be tidy in dress, and above all 
should always keep the hands and nails very clean. 

Frequently much of the food left unserved at the end 
of a meal is wasted. This is unnecessary, since there are 
so many appetizing ways in which food may be prepared 
for the table a second time. To waste food is expen- 
sive, and it is wrong as well. There is another form 
of waste for which the cook is not responsible. Too 
often we are careless about the amount of food that 
we serve to ourselves, or have placed on our plates at 
meal time. Do not take more food than you are quite 
sure you can eat. 



THE NON-NITROGENOUS FOODS 31 

Another way of wasting good food is equally common ; 
that is, eating it improperly. Those who bolt their food 
down are not the only offenders here. If we choose the 
right food and eat it slowly, we may still lose — that is 
waste — much of its value to us by allowing ourselves to be 
in a fretful, anxious, or ugly frame of mind, as we eat. 
The saying that we swallow our thoughts with our food, 
has much sense back of it. A merry breakfast table gives 
all the family a good start for the day. 



CHAPTER V 



ALCOHOLIC DRINKS 




Fig. 5. — A yeast plant, magnified. 



Bacteria and Other Cells. — The tiny seed planted in the 
ground in the spring becomes, before the summer is 
ended, a plant very many times larger than the seed from 
which it sprang. You touch the stalk, the leaves, the 

fruit, and wonder where all 
this material came from. It 
was built up largely of gases, 
which you can neither see nor 
handle, of water, and of a few 
dissolved minerals, which the 
plant sucked up through its 
roots from the moist earth. 
The builders were cells, similar to those that build up 
the animal body. If you cut tiny slices from the stalk, 
the leaves, the fruit, or the root, and examine them 
under the microscope, you can see the different kinds 
of vegetable cells that constructed the plant. 

In the fall, the frost chills these cells and they stop 
their work. If the plant is an annual, it dies. Other 
cells then begin to work, — not cells that build up, but 
cells that tear down and cause the plant to crumble and 
fall apart. The gases and minerals then separate and go 
back to the earth and air from which they came. The 
work of these destructive cells is called according to the 
material they work upon by various names, such as rot, 

32 



ALCOHOLIC DRINKS 33 

mold, putrefaction, fermentation. These are all some form 
of decomposition or decay. The work which they accom- 
plish is the setting free of the building materials, the 
gases, the water, and the minerals, used by th£ building 
cells in forming the living plant or animal body. 

Among the different kinds of cells that cause decay is 
one that sets up the process of fermentation in certain 
sweet liquids. Baker's and brewer's yeast is composed of 
this kind of cells, and another species, called wild yeast, 
floats about in the dust of the air at certain seasons of 
the year and falls with the dust upon the surfaces of 
fruits. See Fig. 5. 

Cider. — The juice of apples, when first pressed from 
the fruit, consists chiefly of water, of more or less sugar, 
and of a small amount of acid. When apples are ground 
and their juice pressed out, the wild yeast cells that were 
in the dust on their stems and skins are washed into the 
juice. If this is left standing in moderately warm air, 
these yeast cells will soon begin their part in the process 
of decay. They cause the sugar of the liquid to break up 
into two simpler substances, carbon dioxide and a poison- 
ous liquid called alcohol. 

While this change is going on, the apple juice appears 
to be full of tiny bubbles rising toward the top, which 
make the juice look like water that is just about to boil ; 
hence the name fermentation (from the Latin " to boil ") 
has been given to this process. Apple juice that has 
fermented is called cider. 

The amount of alcohol in cider depends upon the 
length of time the yeast has been at work and upon the 
amount of sugar in the juice for it to work upon. Ordi- 
narily, in a few hours after the cider comes from the press, 
bubbles of gas can be seen rising through it, indicating 



34: THE ESSENTIALS OF HEALTH 

that the yeast cells are at work breaking up the sugar and 
that some alcohol is already present in the juice. 

" What is the harm in drinking sweet cider ? " is a ques- 
tion frequently asked. If one chooses to use in his own 
home a small hand press and extract at one time only as 
much juice as can be used within five or six hours, and if 
the press be cleaned immediately after each using, so that 
no material is left in it to ferment, he can have sweet 
cider or apple juice that will do no harm. But cider that 
comes from a cider mill may contain considerable alcohol 
and still be called sweet, being more or less contaminated 
with the fermenting and decaying matter about the mill. 
Then, too, the yeast multiplies with almost incredible 
rapidity, a few hours being long enough for a million cells 
to be produced from a single original cell. The change 
of the sugar into alcohol and carbon dioxide goes on with 
corresponding rapidity, for the life processes of the yeast 
cells involve the breaking up of the sugar to get from it 
the oxygen needed for their life and growth. 

The harm, therefore, in drinking sweet cider is that 
one is almost sure to get more or less alcohol, and alcohol 
has the power, even in small quantities, to set up a crav- 
ing for its continued and increasing use. Before the 
revelations of the microscope, nothing was known of the 
existence and mode of life of the yeast and of' other kinds 
of ferments. People knew that apples were good to eat, 
and they naturally supposed the juice of the apple to be 
equally healthful as a drink. The} r could not understand 
why the young man who had always had plenty of cider 
to drink at home should take to going to the tavern or 
saloon for whisky or rum. But w^hen the microscopist 
discovered the germs that cause fermentation, and the 
chemist analyzed the results of their work, it was then 



ALCOHOLIC DRINKS 35 

learned that every fermentation changes the character of 
the substance fermented. Hence, cider that has under- 
gone fermentation differs from the apple juice from which 
it was made, because it contains alcohol, a poison, in 
place of sugar, a food. The danger in drinking cider is 
that the alcohol it contains may arouse the insatiable, 
destructive, alcoholic appetite or craving. 

The same germs that change expressed apple juice 
into an alcoholic liquor will cause a like change in the 
juice of grapes if it is pressed out and allowed to ferment. 
The dried yeast cells floating in the air settle upon the 
surface of the grapes, and when the juice is pressed out, 
they are washed into it and soon set up the process of 
fermentation, which changes the sugar of the grape juice 
to carbon dioxide and alcohol. 

Many people enjoy unfermented grape juice, which is 
made by boiling the juice as soon as it is pressed out of 
the grape. This kills the yeast cells. Then, while boiling 
hot, the juice is sealed in air-tight bottles and thus fer- 
mentation is prevented. Perhaps in time this unfer- 
mented, non-alcoholic wine will come to take the place 
of the fermented. It will be a blessing to the race if 
it does, for as it does not contain the thirst-creating 
poison, alcohol, it will not carry within itself the cause 
of an imperative and progressively increasing demand 
for more. 

Alcoholic wine is to be shunned by every one who 
values the power of self-mastery, of a clear brain, and 
of a sound body. 

Beer. — The process of fermentation is employed also 
to obtain alcoholic drinks from grain. These do not, like 
the fruit juices, contain sugar ready formed within them. 
They contain starch which can be changed to sugar by 



36 



THE ESSENTIALS OF HEALTH 



applying sufficient heat and moisture to sprout the grain. 
When this occurs, the brewer kills the sprouts with a 
higher degree of heat, grinds the grain, then called malt, 
and soaks out the sugar thus obtained with water. To the 
resulting sweet liquid, hops are added and yeast, which 
sets up the process of fermentation. The sugar is changed 
into carbon dioxide and alcohol, which here, as in every 



2 to 8 per cent 
in 

Cider 




Water 


4 to 10 per cent 

in. 

Beer & Ale 




Water 


8 to 15 per cent 

in 

Wine 




Water 


40 to 60 per cent 

in 

Whisky 






Water 



Fig. 6. — A diagram of the proportionate amount of alcohol and water 
in various alcoholic liquors. * 



liquid containing it, has the power of creating the im- 
perious craving for more, while it at the same time 
weakens the will necessary to resist the craving. 

Much emphasis is sometimes laid on the great difference 
between "pure" beer and that which has been "adulter- 
ated," but none of the adulterations ordinarily used are 
as important as the ever present alcohol, because they are 
found in much smaller amounts, and do not possess the 
subtle, dangerous, thirst-compelling power of alcohol. A 
professor in one of our American universities, 1 who made 
a special investigation of the matter of adulterations, said 
that "ethyl [common] alcohol alone is poisonous enough 
to account for all the evils of alcoholism." 

1 Professor Abel, of Johns Hopkins University. 



ALCOHOLIC BRINKS 37 

Germany is often referred to as an example to other 
nations of the advantages of the free use of the best beer. 
Plenty of cheap beer, it is said, will result in less alco- 
holism, because the people will use more beer and less of 
the stronger drinks that contain more alcohol. Within 
the last few years, careful investigators in Germany have 
been looking into the results of beer drinking in that 
country, and this is what one of them reports : * — 

"We now drink nearly four times as much as our yearly 
outlay for army and navy. And what does the alcohol busi- 
ness give us in return for this tribute ? An increasing number 
of criminals, an army of sick and diseased, a depraved future 
generation, a deformed population. To see it, one needs only 
to take a single walk around Munich, the city that lies in the 
fetters of the brewer.' 5 

Distilled Liquors. — The amount of alcohol in fermented 
liquors is limited by the amount of sugar in the original 
liquid to be turned into alcohol and carbon dioxide, and 
also by the fact that ordinary yeast plants cannot work 
in a liquid that contains more than twelve or fourteen 
per cent of alcohol. They are either killed or rendered 
inactive by the poison they have themselves produced. 
So liquors containing a larger per cent of alcohol are 
made by distilling the fermented liquors. 

Alcohol vaporizes at a lower temperature than does 
water. By heating a fermented liquid to the vaporizing 
point of alcohol, the latter rises in the form of vapor, and 
is conducted through pipes to a place of lower tempera- 
ture, where it turns back into liquid form again. Much 
of the water with which it was formerly mixed is left 
behind in the heated vessel, but not all, for some of the 
water turns to vapor and passes over with the alcohol. 
1 Dr. Hermann Popert, LL.D. , of Hamburg. 



38 THE ESSENTIALS OF HEALTH 

Brandy, whisky, rum, gin, are all made by distillation 
from fermented liquors and they sometimes contain as 
high as fifty per cent of alcohol. Some wines not 
distilled are made stronger by having alcohol or distilled 
liquors added to them. Compare proportions in Fig. 6. 

Whether one drinks fermented liquors or distilled ones 
that have been diluted to about the same proportion of 
alcohol matters little. It is the alcohol that is the chief 
source of danger. When the craving becomes so impera- 
tive that the stronger liquors are called for, the poisonous 
effects of the alcohol on various parts of the body make 
the course of destruction more rapid. 



CHAPTER VI 
DIGESTION 

Digestion. — The object of digestion is to dissolve and 
to change the food we eat so that it may be absorbed by 
the body. Scarcely any of the foods are immediately 
available for the wants of the system in the form in which 
w r e take them. They must be changed, and this change 
is brought about by the action of certain liquids or juices 
found in the body known as the digestive juices. These 
juices, also called secretions, are derived from certain 
glands which are called secretory glands. All the secre- 
tions are the direct result of the activity of the cells of 
the secretory glands. 

Excretion. — As the body works, its cells wear out or 
break down. This old or worn-out material must be 
removed from the body. We all know how the wick of 
the lamp must be trimmed and how the candle must be 
snuffed, if the flame is to burn brightly. We must remove 
the ashes from the stove or the furnace in order to make 
the fire burn well. It is much the same with our bodies, 
in which, as we have learned, the food is burned, or more 
properly, oxidized. These waste products of that oxida- 
tion must be removed from the body. There are certain 
glands or organs set apart for the particular work of 
removing these broken-down and worn-out materials ; 
these are called the excretory organs, and the waste wdiich 
they enable the body to throw off is called an excretion. 

39 



40 



THE ESSENTIALS OF HEALTH 



We have, therefore, two great problems to study: How 
nourishment is supplied to the body, and how waste is 
removed from the body. 

The Alimentary Canal. — It is in this canal that the 
process of digestion occurs. Beginning at the mouth, 

the alimentary canal ex- 
tends through the body. 
In the adult, it would, 
if uncoiled, be about 
thirty feet in length and 
it is lined through its 
entire length by a soft, 
velvety tissue called the 
mucous membrane. In 
this membrane are mi- 
nute glands, some of 
which secrete mucus, 
while others secrete 
some of the several di- 
gestive juices. Named 
from above downward, 
there are the following 
parts : the mouth, phar- 
ynx, oesophagus, stom- 
ach, small intestine, and 
large intestine. A study 

Fig. 7. — The alimentary canal: (1) the ° „ .,, ., . 

oesophagus; (2) the stomach; (3) the py- °* *lg. 7 Will aid 111 

lorus; (4) the gall bladder; (5) the duct understanding the loca- 

carryingbiletotheintestm^ (Q the duct ^ d f f these 

from the pancreas ; (7) the small intestine; 

(8) the large intestine ; (9) the appendix. several parts. 

The pharynx starts at the back of the nasal passage 
and extends about four and one half inches down the 
neck, where it becomes continuous with the oesophagus. 




DIGESTION 41 

The oesophagus, see Fig. 7 (1), is about nine inches in 
length, and extends from the pharynx to the stomach. 
The stomach (2) is the most dilated portion of the canal. 
It lies transversely in the abdominal cavity (which also 
holds the liver, intestines, kidneys, and other organs not 
concerned with digestion), and is connected below with 
the small intestine (7). The small intestine is about 
twenty feet in length, and terminates in the large intes- 
tine (8), which is about five feet in length. It will be 
noticed that the small intestine occupies the center of the 
abdominal cavity, while the large intestine passes around 
the borders of the cavity. All of Fig. 7, except (1), 
represents that part of the alimentary canal situated in 
the abdominal cavity. 

The Peritoneum. — Nearly all the abdominal cavity is 
occupied by the organs of digestion. Lining this cavity, 
and covering more or less perfectly all these organs, is a 
thin, delicate membrane, called the peritoneum. 

The Appendix. — The vermiform appendix is a tube 
about the size of a slate pencil and three or four inches 
in length. It is situated on the right of the lower part 
of the abdominal cavity. The appendix opens from the 
large intestine at the point where the small intestine 
joins it. At the further end it is closed and it floats in 
the abdominal cavity. Its purpose in the body is not 
understood, and scientists have readied the conclusion 
that it is not now of use, but is a curious remainder from 
some organ that was once, perhaps in prehistoric times, 
active in the human body. As it opens from the large 
intestine, some of the w T aste matter there may enter it. 
Inflammation is sometimes set up, giving rise to the 
disease known as appendicitis. Surgeons frequently oper- 
ate for this disease, entirely removing the appendix. This 



42 THE ESSENTIALS OF HEALTH 

operation is considered one of the great achievements of 
modern surgery. 

Mastication. — Mastication, or chewing, consists in cut- 
ting and grinding the food by the teeth. It is purely a 
mechanical process, yet it is necessary in order that the 
food may be better prepared for the action of the diges- 
tive juices ; the finer the particles of food are, so much 
the better can these juices act upon them. 

One very important result accompanying mastication 
is the thorough mixing of the food with the saliva. As 
a result of this, the food is moistened and prepared for 
swallowing, while at the same time some of its starchy 
elements are changed into sugar. The solid and semi- 
solid foods should be chewed very fine. One of the most 
common causes of stomach trouble is incomplete mastica- 
tion, a result of too rapid eating. Let no food pass down 
the throat that is not finely chewed. 

Form and Function of Teeth in Animals. — As the habits 
and foods of animals differ, so do their teeth vary in form 
and function, in order best to serve particular needs. 

Fishes and serpents, that swallow 
their food entire, have no need 
for any cutting or grinding teeth. 
The function of the teeth in these 
animals is restricted to seizing and 
Fig. 8. - The skull of a snake. holding the f 00(L Therefore their 

teeth are sharp and curved, with the points set backward, 
so that when once the prey is caught it is very difficult 
for it to escape. In the horse and allied animals there 
are two kinds of teeth, — those in front, the incisors, for 
cutting off the herbage ; and those farther back, the 
molars, for grinding. Compare Figs. 8 and 9. 

In the gnawing animals, as the rats, mice, and squirrels, 




DIGESTION 



43 




Fig. 9. — The skull of a horse. 



the incisor teeth are remarkably developed. Their edges 

are sharp and chisel-shaped, and they are directly opposed 

to each other in the upper and lower jaws. They are 

peculiar also in their growth. As the ends are worn away, 

the teeth are pushed up 

from their roots, thus 

keeping their normal 

length. Sometimes one 

of these animals has 

one of its incisor teeth 

broken off, or injured 

so that it fails to grow. 

The corresponding tooth 

in the other jaw then has no tooth against which to cut, 

and hence it is not worn away. It keeps on growing, 

occasionally to such a length that it prevents the animal 

from getting its food, and thereby causes its death. 

Development and Growth of Teeth in Man. — In man, the 
teeth are at first masses of soft tissue within the jawbones. 
They gradually assume their characteristic shapes, and are 
fully formed before they appear through the gums. They 
are not capable of self-repair ; neither do they grow nor 
change in shape after they are once formed. As already 
explained, the teeth are most important aids to digestion. 

Two Sets of Teeth. — The jaws of a child are not so 
large as those of an adult, hence they cannot hold as 
many teeth. To compensate for this, there are two sets 
of teeth. The teeth of the first set are called the milk or 
temporary teeth, and the teeth of the second set are called 
the permanent teeth. 

The first teeth of the temporary set appear about the 
sixth or seventh month ; they come one by one, until the 
whole set of ten for each jaw is complete by the end of 



44 



THE ESSENTIALS OF HEALTH 



the second year. In the fifth or sixth year, these milk 
teeth begin to loosen and are removed, and the permanent 
teeth begin to appear. At twelve or thirteen years of 
age, the full set of permanent teeth is present, except 
the wisdom teeth. These usually do not appear until the 
person is twenty or twenty-five years of age. The per- 




Fig. 10a. — The teeth of an adult: (1) an incisor, or cat- 
ting tooth ; (2) a canine, or eyetooth ; (3) molar of the 
lower jaw; (4) molar of the upper jaw. Fig. 10 6. — Sec- 
tion of a tooth. 




Fig. 10 6. 



manent teeth are thirty-two in number, sixteen for each 
jaw. See Fig. 11. They are fully developed in the jaw- 
bones, beneath the temporary teeth, before they appear. 

The Structure of Teeth. — Each tooth consists of the 
crown, or the part projecting into the mouth ; the neck, 
or the part surrounded by the gums ; and the root, or 
the part deeply seated in a bony socket. When broken 
open, a tooth is seen to be hollow. Fig. 10 5, a section of 
the incisor, illustrates the shape of this central cavity, 
showing how it conforms to the general outline of the 
tooth, and thus varies in form for the several teeth. In 
the living tooth, this cavity is filled with nerves and blood 
vessels, which are held together by a delicate connective 
tissue." This is called the pulp of the tooth. When in- 
flamed, it gives rise to a most intense toothache. 



DIGESTION 



45 



Surrounding the crown of the tooth is the hardest sub- 
stance in the body, called the enamel ; around the root 
is a thin layer of bone, called cement; but the greater 
part of the tooth consists of a hard substance, called 
dentine, or ivory. The dentine surrounds the pulp 
cavity and extends outward to the enamel and cement : 




Fig. 11. — A side view of the lower jaw with the outer walls of bone re- 
rrioved, showing the teeth in proper place: (1) the two incisors; (2) the 
canine; (3) the two bicuspids ; (4) the three lower molars (the last molar is 
sometimes called the wisdom tooth) ; (5) a blood vessel ; (6) a nerve. 



in structure it is like the tusk of the elephant, harder 
than bone, but not so hard as the enamel. 

The figure shows that a tooth is pierced with in- 
numerable fine canals that extend from the pulp *to the 
very outside edge of the dentine. These canals are filled 
with fibers of living matter which are connected with 
the cells of the pulp. With the exception of the enamel, 
therefore, a tooth is a living tissue, having nerves and 
blood vessels in its center, bone cells in the cement 
around its roots, and innumerable fibers of tissue pene- 



46 THE ESSENTIALS OF HEALTH 

trating the dentine. With this knowledge, it no longer 
seems strange that decay should make the teeth ache, 
and that extracting them should cause pain. Yet with 
all this living matter entering into their structure, the 
teeth cannot repair themselves when injured. They 
should receive the best of care. 

Care of the Teeth. — The necessity of having good teeth 
in order to present an attractive personal appearance, 
as well as the important relation of the teeth to the 
digestive function, is so evident that it is surprising so 
little attention is given them. They should be cleaned 
at least once each day; better after each meal. Use some 
pure dentifrice, either in liquid or in powder form. 

The Decay of Teeth. — Some teeth decay much more 
easily than others that are made of better substance. A 
lack of proper food and poor health at the time Avhen the 
teeth are forming interfere with their growing hard and 
firm. It is now known that germs are the actual cause of 
the decay of teeth. The growth of these germs is greatly 
aided by the natural moisture and warmth of the mouth, 
-and also by the presence of particles of food that may 
carelessly be left around the teeth after eating. A dentist 
should be consulted as soon as a tooth gives pain, or if 
a cavity is discovered, in order that the trouble may be 
remedied before the tooth structure is seriously damaged. 
To prevent decay and to preserve the teeth, keep them 
clean. Some persons give the best of attention to their 
teeth when they are well, but absolutely neglect them 
when ill. In this way the teeth are often badly injured. 
During illness the secretions of the mouth are often bad 
and so the teeth need extra care at such a time. 

The Saliva. — The saliva is a fluid which flows into 
the mouth mainly from three pairs of glands, called the 



DIGESTION 



47 



salivary glands, situated three on each side of the mouth. 
Mixed with the saliva is some mucus from the mucous 
glands found in the lining membrane of the mouth. One 
pair of the salivary glands, the submaxillary glands, is 
situated in the floor of the mouth between the two sides of 
the lower jawbone. Another pair, the sublingual glands, 
is situated beneath the tongue. The secretions of these 
glands are conveyed through little ducts which open into 
the mouth just beneath 
the tongue. The third 
pair of glands, the paro- 
tid, is situated a little 
below and directly in 
front of the ears. 
When inflamed, these 
glands become swollen 
and painful, as in 
the disease known as 
44 mumps." This inflam- 
mation is due to a germ. 
The germs may be car- 
ried from one who is ill 
with the disease to some one else who has not yet had it, 
giving him the disease. Hence we say that it is contagious. 
A drop of the saliva examined under the microscope 
shows a number of old cells that have fallen from the lin- 
ing membrane of the mouth. The vast number of these 
cells always found in the saliva gives another striking 
proof that the body is rapidly and continuously changing ; 
for new cells must take the place of the old, as fast as the 
latter are removed. Fig. 12 illustrates these old cells 
together with others which have escaped from the lym- 
phatic vessels, called lymph corpuscles. 




Fig. 12. — Cells found in the saliva, mag- 
nified: (1) epithelial cells from the mucous 
membrane lining the mouth; (2) lymph 
corpuscles that have escaped from the lym- 
phatics of the mouth. 



48 THE ESSENTIALS OF HEALTH 

Uses of Saliva. — The saliva is a constant secretion, 
although it can be greatly increased by the movements 
of the jaws, especially when food is being masticated. 
It is essential in order to keep the tissues about the mouth 
and the throat moist. If the mouth is dry, speaking is 
extremely difficult, as many a young orator knows when 
the nervousness caused by a first appearance in public 
temporarily checks the secretion of saliva. 

The principal function of the saliva is to moisten the 
food, and thus aid in its mastication and solution ; for it 
is very difficult to swallow anything that is hard and dry, 
unless first moistened with some fluid. By dissolving cer- 
tain substances the saliva enables us to taste them ; for 
solid bodies cannot be tasted. A chemical examination 
of the saliva shows that it contains a peculiar substance 
called ptyalin. It is this ingredient which gives the 
saliva its power to change starch into sugar ; but, owing 
to the short time the food is kept in the mouth, only a 
small amount of the starchy foods is thus changed. We 
shall learn later that this important change occurs prin- 
cipally after they leave the stomach. 

As one object of the saliva is to furnish moisture, so 
that the food may be more readily swallowed, it follows 
that it is not necessary to wash down the food with large 
quantities of some fluid ; indeed, it is much better that the 
food should be mixed with the saliva than with any other 
liquid. As a rule, the saliva furnishes moisture enough, 
as from one to three pints are secreted each day. While 
there is no harm in using a moderate amount of water with 
our meals, yet large quantities are certainly injurious, 
especially if the liquids are either very hot or very cold. 

Promiscuous Spitting. — Spitting in public places is not 
only an exhibition of bad manners, but it is a menace to 



DIGESTION 49 

the public health. It is a fact that in the mouth of per- 
sons who are apparently in good health, the germs of such 
diseases as diphtheria, pneumonia, and consumption are 
frequently found. These persons may never contract any 
of these diseases, for the vigorous, healthy body can resist 
many germs ; but other persons may not have so much of 
this resistive power, and should these germs once reach 
them, they might not be able to withstand the attack. 
Let us see how easily these germs may pass from one 
person to another. When secretions from the throat and 
mouth are deposited in public places, they soon become 
dry and are easily crushed to a powder, which floats in 
the dust of the atmosphere. In this condition these germs 
may be inhaled by those who are in fairly good health and 
may be the direct cause of producing disease. Therefore, 
spitting in public places is now declared a nuisance in 
many of the large cities, and is strictly forbidden by law ; 
one who indulges in it is liable to punishment by fine, by 
imprisonment, or by both. 

The Pharynx. — The pharynx is partly divided from the 
mouth by a curtain hanging down from above, called the 
soft palate. It is thus named to distinguish it from 
the hard palate, which forms the roof of the mouth. From 
the center of the soft palate, there is a prolongation down- 
ward, the uvula, often incorrectly called the palate. In 
the upper part of the pharynx, on a line with the floor 
of the nasal passages, are the openings of two tubes, called 
the Eustachian tubes. Each tube extends from the side 
of the upper part of the pharynx to the middle ear. The 
openings of these tubes cannot be seen by looking into 
the throat, because they are behind the soft palate. 

The Tonsils. — On each side of the throat, below the soft 
palate, is a small round body called the tonsil. The tonsils 



50 THE ESSENTIALS OF HEALTH 

i 
are sometimes permanently enlarged. If the enlargement 

is sufficient to interfere with speech or with the swallow- 
ing of food, a physician should be consulted about remov- 
ing them. When a severe inflammation of the tonsils 
occurs, it is known as tonsilitis. 

Deglutition or Swallowing. — After the food has been 
masticated, it is forced to the back of the mouth by the 
tongue and other parts of the mouth and it passes into 
the pharynx. The muscular walls of the pharynx and 
oesophagus continue to contract just behind the food, 
thereby pushing it into the stomach. Thus swallowing 
is a muscular act. This accounts for the fact that the 
horse and many other animals can drink with the mouth 
held below the throat ; that is, when they drink the water 
runs up hill, because it is pushed up. 

As the food passes down the pharynx, it is prevented 
from entering the windpipe by a lid called the epiglottis, 
which shuts tightly down upon the windpipe and over it 
the food passes. Occasionally a small amount of food or 
drink gets into the air passages, causing violent coughing. 

The time that elapses from the beginning of deglutition 
until the food reaches the stomach is not more than one 
tenth of a second. 



CHAPTER VII 



DIGESTION IN THE STOMACH AND THE INTESTINE 



The Stomach. — The stomach is between the oesophagus 
above and the small intestine below, and is situated in the 
left upper side of the abdominal cavity. It is the prin- 
cipal organ of di- 
gestion. In the 
adult it is capable, 
when moderately 
distended, of hold- 
ing about three 
pints. The capac- 
ity of the stomach 
of a new-born child 
is about one ounce. 
The left side of the 
stomach is called 
the cardiac portion, 
so named because 
it is the part nearer the heart. The right side is called 
the pyloric portion, so named from a Greek word meaning 
" gate-keeper." The food enters the stomach through 
the oesophagus at the cardiac end, and leaves it at the 
pyloric end, which is at the left of Fig. 13. 

The Pyloric Opening. — The opening through which the 
food must pass from the stomach to the small intestine is 
called the pyloric opening. It is well guarded by a valve. 

51 




Fig. 13. —View of the inside of the stomach. 
The front walls have been cut away, showing the 
mucous lining arranged in folds or plaits. 



52 



THE ESSENTIALS OF HEALTH 



During the early stages of digestion this valve remains 
closed m order that there maj^ be time for certain foods 



I 



M^StXJ?h M\ jr^^X^K 



I 




to be acted upon by the 
gastric juice. As diges- 
tion proceeds, the valve 
opens now and then for the 
escape of the food ; later, 
towards the close of diges- 
tion, it fs open nearly all 
the time. 

Fig. 14. — A cross-section of a small The Gastric Glands. — 111 

portion of the walls of the stomach, the mucous membrane of 

slightly magnified, showing the glands. the stomach are found vast 

numbers of minute glands, called the gastric glands. 
These are of the nature of tubes, or canals, lined with 
cells which secrete a juice called the 
gastric juice. Whenever food is taken, 
this juice is poured into the stomach 
through the openings of the glands. 

Fig. 14 illustrates a section of a small 
portion of the walls of the stomach. If 
this section were viewed from above, the 
minute depressions would appear as cir- 
cular openings; they are the openings 
of the glands. Fig. 15 illustrates some 
of these glands magnified, and Fig. 16 
shows one of the glands very highly 
magnified. A careful examination of Fig. 15.- Glands of 

° . the stomach, as seen 

this figure shows two kinds of cells m w i tn a microscope, 
the lower part. 

The Gastric Juice. — The gastric juice is clear and 
colorless, in this respect resembling water. But it con- 
tains two marked ingredients not found in water ; these 




DIGESTION IN THE STOMACH AND INTESTINE 53 

are pepsin and an acid called hydrochloric acid. It is now 
known that there are some cells in the gastric glands that 
secrete the pepsin, while other cells secrete the acid. 

When the stomach is empty and its mucous membrane 
thrown into folds, the membrane is of a pale red color, 
and there is no secretion of the gastric juice. Upon the 
introduction of food, the mucous membrane rapidly fills 
with blood, becomes bright red in color, and secretes the 
gastric juice in abundance. Not all 
foods are digested in the stomach by 
the gastric juice ; the oily and starchy 
foods pass out of it unchanged. 

The chief characteristic of the gastric 
juice is its power to dissolve and digest 
the proteids in foods. If only the 
proper amount of these be taken, they 
are completely digested in the stomach ; 
but if more be taken than can be di- 
gested by the gastric juice, they pass 
out into the intestine, where the work 
is completed by the pancreatic juice. 
We shall learn that the pancreatic juice 
possesses the same power to digest fig. 16.— A gland 
proteids as the gastric juice. It is of the stomach, 
estimated that the stomach of a healthy higllly ma ^ ified - 
adult secretes from ten to twenty pints of gastric juice 
each day. 

Action of Gastric Juice on Different Foods. — As has been 
stated, the proteid foods, such as the lean meats, the white 
of egg^ etc., are digested in the stomach. The gluten 
in bread is liquefied and digested in the stomach, but 
the starch in it is unaffected. Fatty foods, as the fat of 
flesh, are acted upon but slightly by the gastric juice, and 




54 THE ESSENTIALS OF HEALTH 

only in this way, — the gastric juice liquefies the tissue 
that surrounds the fat globules, thus allowing the fat to 
escape in the form of oil drops. But upon the fat itself 
the gastric juice has no effect ; the fat passes out of the 
stomach unchanged. Milk is coagulated, or curdled, soon 
after it reaches the stomach. This change is now believed 
to be due to the action of a distinct ferment that exists 
in the stomach. Whatever the cause, a curd is formed, 
and this curd is called casein. The gastric juice digests 
the casein, but does not affect the oil drops, or fat. The 
vegetable foods are digested in a manner similar to that 
already described. The albuminous parts are dissolved 
and digested, while the oily and starchy ingredients are 
set free to pass out of the stomach unchanged. As the 
contents of the stomach begin to pass through the pyloric 
orifice into the intestine, they consist of digested albumi- 
nous foods, of undigested starch, and fat, and of much 
indigestible material. To this mixture the name chyme 
has been given. 

Movements of the Stomach. — As soon as the food 
reaches the stomach and the secretion of the gastric juice 
commences, the muscular walls of the stomach begin to 
contract. These contractions produce such a movement 
of the contents of the stomach that the food and gastric 
juice are thoroughly mixed. The food is thus carried 
back and forth, to every part of the stomach, so that the 
whole mass may be penetrated thorough^ by the gastric 
juice, and digestion go on simultaneously in all parts. 

Conditions affecting Digestion. — The solid foods are 
more easily digested if the pieces be minutely divided ; 
therefore when large pieces of food are swallowed, diges- 
tion is retarded. Food should be eaten slowly, that the 
gastric juice may be formed in sufficient quantity to be 



DIGESTION IN THE STOMACII AND INTESTINE 55 



thoroughly mixed with it as it is swallowed. If the food 
be eaten slowly, there is but little danger of overloading 
the stomach, but rapid eating is quite likely to result in 
overeating, which leads to many troubles. 

The following table (h = hours ; m = minutes) will 
give a fairly correct idea of the average time required for 
the digestion of several different foods, including those 
digested in the stomach and those which undergo this 
process farther down the alimentary canal. 



Easy of Digestion 



More Difficult 



Rice, boiled . . 
Apples, sweet, raw 
Milk .... 
Cabbage, raw . 
Oysters, raw . 
Potatoes, baked 
Lamb, broiled . 
Chicken, boiled 
Eggs, soft boiled 
Custard, baked 
Beef, broiled . 
Mutton, broiled 
Beef, roasted . 



00 
30 
00 
00 
30 
30 
30 
45 
00 
00 
00 
00 
00 



h m 



Potatoes, boiled . 
Oysters, fried . . 
Eggs, hard boiled 
Bread, fresh . . 
Pork, broiled . . 
Veal, roasted . . 
Beef, fried . . . 
Veal, fried . . . 
Cheese .... 
Cabbage, boiled . 
Duck, wild, roasted 
Pork, fried . . . 
Pork, roasted . . 



30 
30 
30 
30 
30 
30 
00 
00 
00 
30 
30 
30 
15 



In the case of the average meal, with its variety of 
foods, a healthy person would usually complete digestion 
in between three and four hours. 

Drinking hastily a glass of very cold water might be 
sufficient to drive the blood from the mucous membrane 
of the stomach and check the action of the glands. It 
might require some time for them to recover from the 
shock of the cold, during which but little, if any, gas- 
tric juice would be secreted. This delay would prolong 
digestion and be quite likely to produce some form of 



56 THE ESSENTIALS OF HEALTH 

stomach trouble. Too much liquid with a meal dilutes, 
and therefore weakens, the gastric juice. It is much 
better to quench the thirst before going to the table. 
Mental and physical fatigue will interfere with digestion ; 
therefore one should never eat a hearty meal when very 
tired, either from manual labor or from severe mental 
exercise. A short rest of a few moments before going to 
the table is a wise precaution in such cases. It is also 
true that tranquillity of temper has much to do with the 
proper digestion of food. " 

The Liver. — The liver is the largest gland in the body. 
It is situated in the upper part of the abdominal cavity, 
just beneath the diaphragm. The greater portion of it is 
on the right side of the body, although some of it ex- 
tends over to the left side. A reference to Fig. 39 
will give an idea of its location, as well as of its relation 
to the diaphragm and to the stomach. The microscope 
shows that the liver consists largely of cells. These 
cells secrete a fluid, called bile, or gall. The liver is 
constantly secreting this bile. During the intervals 
of digestion, the bile collects in a sac, situated on the 
under side of the liver and called the gall bladder. The 
bile may pass directly from the liver into the intestine 
through a duct, shown in Fig. 17, at (7), or it may first 
collect in the gall bladder and pass into the intestine 
through another duct, at (8). These two ducts, however, 
unite into one, at (9), forming one large bile duct. Just 
before this duct opens into the intestine, it unites with 
the duct from the pancreas, and the two terminate in a 
common opening, as shown at (10). 

The Bile. — From two to three pints of bile are secreted 
each day. Many experiments have proved that if this 
secretion be prevented from entering the intestine, or if 



DIGESTION IN THE STOMACH AND INTESTINE 57 



the liver should fail to produce it, sickness and death will 
follow. When the ducts leading from the liver to the 
intestine become stopped up in any way, so that the bile 
is held back, the blood vessels absorb the bile and carry 




Fig. 17. — A. diagram illustrating the position of the pancreas and its re- 
lation to surrounding parts : (1) the stomach ; (2) the pylorus ; (3) the small 
intestine ; (4) the spleen ; (5) the pancreas ; (6) the duct of the pancreas : (7) the 
bile duct from the liver ; (8) the bile duct from the gall bladder ; (9) the com- 
mon bile duct, formed by a union of the two bile ducts. The common bile 
duct unites with the pancreatic duct, and the one duct thus formed opens into 
the small intestine at 10. 

it to all parts of the body. This makes the skin yellow, 
as in cases of jaundice. The bile aids in the digestion 
and absorption of the oily and fatty foods. It moistens 
the walls of the intestine and renders their contents 
more liquid. It also does much to prevent the decom- 
position of food while it is in the intestinal canal. 
The bile has another very important function ; it acts 



58 THE ESSENTIALS OF HEALTH 

as a natural laxative. A diminished secretion of bile 
produces constipation, while an excessive secretion causes 
bilious diarrhea. The term " biliousness " is quite mis- 
leading, but it generally relates to either one or the other 
of the above conditions. 

The Liver Sugar. — We know that all the starchy foods 
must be changed into sugar before they can be absorbed ; 
therefore all the starch and sugar taken into the body 
are finally absorbed as so much grape sugar. This sugar 
is carried directly to the liver, where it undergoes a 
slight change. The liver stores it in its cells, only to 
give it up again to the blood as the needs of the body 
demand. 

The Pancreas. — The pancreas is a long, thin gland 
situated just below and behind the stomach; it is about 
six inches in length. The duct from this gland opens 
into the intestine, in common with the bile duct, about 
four inches below the pylorus. In the lower animals, 
the pancreas is known as the sweetbread. 

The pancreatic juice has a direct action on all fatty 
and oily foods. It is the only digestive juice that is 
able to completely digest the fats and prepare them for 
absorption. It changes^ them into a white,, opaque liquid 
called chyle. When examined with the microscope, chyle 
is found to consist of extremely minute particles of fat or 
oil. When any fat or oil is thus changed, it is called an 
emulsion. All fats must be turned into an emulsion before 
they can be absorbed. The pancreatic juice is also capable 
of changing the starches into sugar, completing the work 
which was begun by the saliva, and also of digesting proteid 
foods, although this is principally done in the stomach. 

Contraction of the Intestines. — By the contraction of 
the walls of the stomach the food is forced into the small 



DIGESTION IN THE STOMACH AND INTESTINE 59 

intestine ; and by the contraction of the walls of the 
intestine, the food is still further moved along the 
alimentary canal, where it mingles with other digestive 
juices and is more or less absorbed. In health we are 
not conscious of these movements, but if, because of any 
unusual conditions, they become more rapid, or more 
strong than usual, they give rise to griping and to 
severe pains. 

The Intestinal Juice. — Situated in the mucous mem- 
brane of the small intestine are minute glands ; these 
secrete a digestive fluid, called the intestinal juice. It 
aids in the digestion of the foods, principally of the 
starches and the fats. 

Effects of Alcohol on the Stomach. — When wine, whisky, 
beer, or any other alcoholic liquor comes into contact with 
the mucous membrane of the stomach, it causes an increased 
flow of blood there. Irritated by the presence of the 
alcohol, the glands throw out an extra quantity of gastric 
juice. On this account alcohol is considered by some an 
aid to digestion, but physiologists who have studied the 
matter say that the presence of the food itself should 
be a sufficient stimulus, and that the overwork thus 
thrown upon the glands by the alcohol soon weakens 
them so that they throw out an imperfect juice. The 
mucous membrane becomes constantly red or inflamed, 
later the glands become smaller, and permanent indiges- 
tion results. 

Such an inflamed condition of the stomach is called 
gastric catarrh. The inflammation causes an unnatural 
heat in the stomach, together with a sickening, faint 
feeling. To quiet the burning sensation and to quench 
its accompanying thirst, more liquor is taken. This 
appears to give relief ; but the relief is of a most decep- 



60 THE ESSENTIALS OF HEALTH 

tive kind. The alcohol simply deadens for a short time 
the nerves of the stomach. The apparent temporary 
relief is to the drinker a sufficient excuse for his con- 
tinuing its use. Again and again is this experiment 
repeated, while the inflamed stomach remains a witness 
to the folly of trying to put out a fire by continually 
adding more fuel. Persons thus addicted to the use of 
alcoholic drinks many times make earnest effort to do 
without them ; but the craving of the inflamed stomach, 




Fig. 18. — A, liver cells, highly magnified, from a healthy liver. B, liver 
cells, highly magnified, from a fatty liver, the oil globules take the place of 
healthy liver substance. 

the unnatural thirst, and the strong appetite, all appeal 
for more drink. 

Effect on the Liver. — The secretion of bile and the 
storing up of the liver sugar can only be carried on 
properly in a healthy liver. Each cell must be ready to 
do its part. When drinks containing alcohol are taken, 
the blood vessels carry the alcohol directly to the liver, 
frequently causing that gland to become large and fatty. 
In these cases the microscope shows that each cell has 
become filled with minute globules of fat. Such a con- 
dition is represented in Fig. 18, at B. These fat globules 



DIGESTION IN THE STOMACH AND INTESTINE 61 

cannot make bile, neither can they store up the liver 
sugar ; therefore the liver becomes a mass of fatty 
tissue, unable to do its work. 

After the long-continued use of alcoholic beverages, 
especially whisky, brandy, and gin, the liver undergoes 
other changes. It becomes greatly reduced in size and 
much too hard. Such a liver is so characteristic of 
alcohol poisoning that medical authorities have given 
it the distinct name of the " drunkard's liver." The 
microscope shows the cells of such a liver to be much 
reduced in size, and otherwise changed in appearance. 

When the liver cannot perform its functions properly, 
the health of the whole body will, sooner or later, become 
seriously affected. Alcohol does not interfere simply 
with the functions of the liver, but it strikes deeper, and 
actually changes the very structure of that important 
organ. 

Effects of Tobacco on Digestion. — Digestion is often 
impaired in those who use tobacco. By chewing tobacco, 
the salivary glands are constantly overworked, so that 
when the saliva is most needed, at mealtime, an insuffi- 
cient amount is furnished. This necessitates the use of 
some other liquid to moisten the food; therefore an ex- 
cessive amount of water, tea, or coffee is used. The more 
general effects are of a secondary nature. The nicotine 
is absorbed in* sufficient amount to affect the nervous 
system, giving rise to a kind of indigestion called nervous 
dyspepsia. 



CHAPTER VIII 
ABSORPTION 

Definition of Absorption. — It has been stated in a pre- 
vious chapter that the insoluble starchy foods are changed 
into the soluble grape sugar, by the saliva and the pancre- 
atic juice ; that the lean meats, eggs, and other albuminous 
foods are digested by the gastric juice, and that the fats 
are changed by the pancreatic juice. If our foods could 
be absorbed in their natural state, this complicated work 
of digestion would be unnecessary. But we know that 
the foods must first be liquefied and changed, before they 
can be taken up by the proper vessels and carried to the 
various parts of the body. 

Absorption, therefore, is the process by which the 
digested food passes from the alimentary canal into the 
blood vessels and the lymph vessels. 

Absorption from the Stomach. — The water that is taken 
as drink, and also that found in the food, is not to any 
great extent absorbed from the stomach, but passes, after 
a short time, into the intestines. There is a slight absorp- 
tion, from the stomach, of sugar and of the changed 
albuminous foods ; but the process of absorption takes 
place principally in the intestines. 

Structure of the Small Intestine. — The outer walls of 
the small intestine are composed of involuntary muscle, 
which is directly continuous with that forming the walls 
of the stomach. Within this muscular wall, and attached 

62 



ABSOliPTIOX 



63 



to it, is a mucous membrane which lines the whole of the 
small intestine. This mucous membrane is arranged in 
folds, or plaits, which pass around and transversely to 
the canal. Some'of the folds are nearly two thirds of an 
inch in depth at their broadest part, though most of them 
are smaller. These folds retard the passage of food along 




Fig. 19 a. — Diagram of a cross section of the small intestine : (1) lacteal 
or lymphatic vessels ; (2) blood vessels ; (3) villi. 

Fig. 19 b. — A villus of the small intestine, magnified : (1) central lym- 
phatic; (2) blood vessels. 

the intestine, and also increase the surface for absorption. 
Projecting from these folds, and covering their inner sur- 
faces, are very minute elevations, called villi. They are 
from -g 1 ^ to -^ of an inch in length and they hang down 
toward the center of the canal like so many minute fin- 
gers. They give to the mucous membrane its velvety 
appearance. It is estimated that there are fifteen or 
twenty million of these villi in the small intestine. 

Fig. 19 a illustrates the general arrangement of the vari- 
ous parts as seen in a cross section of the small intestine. 
The outer wall is thick and firm, composed of strong mus- 



64 THE ESSENTIALS OF HEALTH 

cular tissue. Within this are represented the villi, hang- 
ing down toward the center of the canal. Two kinds of 
vessels are illustrated in the drawing, — the blood vessels 
and the lymph vessels ; the latter are also known as the 
lymphatics, or the lacteals (from the Latin word lac, 
" milk "), because when found in the villi they look white. 

A careful study of one of these villi is necessary for a 
clear understanding of the subject of absorption. At 
Fig. 19 b is a single villus, highly magnified. Each of 
those represented in Fig. 19 a would appear the same under 
an equally high magnifying power ; in fact, this single 
villus may be taken as a representative of the twenty mil- 
lion found in the body. Each villus is surrounded with 
a layer of minute cells. Directly in the center (1) is 
a darkly shaded vessel ; this is the lacteal, or lymphatic 
vessel. It begins at the free end of the villus and unites 
with the lacteals from the other villi, as clearly seen in 
Fig. 19 a. Surrounding the central lymphatic are numer- 
ous capillary blood vessels. A reference to Fig. 19 a shows 
that the capillaries from several villi unite to make the 
larger blood vessels, at (2). The villi, therefore, consist of 
two kinds of vessels, surrounded by a layer of cells. 

Absorption from the Small Intestine. — The central lym- 
phatics, or lacteals, of the villi are especially concerned in 
the absorption of the digested fatty foods. The blood 
vessels of the villi absorb the other digested foods, as 
grape sugar and the albuminous foods. This is the gen- 
eral rule, although it is a fact that each system of vessels 
may absorb all kinds of digested food. Water and many 
watery solutions are freely absorbed while in the small 
intestine. 

Absorption from the Large Intestine. — From the fact 
that there are no villi in the large intestine, we conclude 



ABSORPTION 65 

that the absorption of digested foods was largely completed 
in the small intestine. Yet, without doubt, any foods 
which may have escaped absorption in the small intestine 
may be absorbed while in the large intestine. But the 
principal work of absorption in the large intestine is 
confined to the absorption of water. The contents pass 
through the large intestine very slowly, the average time 
required for the passage being in the vicinity of twelve 
hours. 

The Portal Vein. — The blood vessels of the villi unite 
with other blood vessels from the stomach to make a large 
vein, callei the portal vein. This vein goes directly from 
the stomach and the intestine to the liver. It carries the 
digested foods, taken up by the blood vessels, to the liver. 
At the proper time, this food will pass from the liver 
through certain veins, directly to the heart. From this 
central point, it is soon sent out to all parts of the body. 

Lymphatic Vessels and Glands. — The lymphatic vessels 
may be well compared to the veins, for they begin as 
minute capillaries which become larger and larger until 
they approach the heart. All along the course of the 
lymphatic vessels are great numbers of round bodies 
varying in size from a mustard seed to a bean. These 
are the lymphatic glands. Many of the lymph vessels pass 
directly through these glands on their way to the heart. 

The Lymph. — The watery part of the blood is con- 
stantly passing through the thin walls of the blood capil- 
laries. Being then outside of the blood vessels, it is no 
longer called a part of the blood, but is given the name of 
lymph. It keeps the delicate cells in a moist condition 
and is an aid to the proper performance of the nrysterious 
processes of nutrition. When this liquid first escapes 
from the capillaries, it is rich in nourishment. The cells, 



66 THE ESSENTIALS OF HEALTH 

however, take from it just those elements necessary for 
their proper nourishment and growth, and it thus loses its 
most nourishing ingredients. At the same time that the 
cells are taking up the nourishment from this lymph, they 
are also giving back to it their worn-out and useless 
material. Each cell takes its new food and gives off its 
waste material. 

It is the general object of the lymph vessels to collect 
this used-up lymph and bring it back to the blood. Al- 
though we have seen that the lymph is not at first con- 
fined to the walls of any vessel, yet it soon enters the 
openings of minute lymph capillaries, and these soon be- 
come the large lymph vessels which at last enter the veins 
near the heart. Thus we learn that the flow of lymph is 
always in the direction toward the heart. 

The Thoracic Duct. — Directly in front of the spinal 
column lies a tube called the thoracic duct. It is from 
eighteen to twenty inches in length, in the adult, and is 
about the size of an ordinary slate pencil. This duct 
carries the greater part of all the lymph and chyle 
into the blood ; it is the central, large vessel for all the 
lymphatics of the body. There are numerous valves 
throughout its entire length, so arranged that they com- 
pletely prevent the lymph and chyle from falling toward 
its lower part. The duct begins in the lower part of the 
abdominal cavity by a triangular enlargement, and then 
passes up through the diaphragm. When near the heart, 
it makes a sharp curve and empties into a large vein 
beneath the left collar bone. This vein carries the lymph 
directly to the right side of the heart. Thus the lymph 
enters the general circulation. 

The lymph from the upper part of the right side of the 
body reaches the circulation through another lymphatic 



ABSORPTION 67 

duct of small size. It empties into a corresponding vein 
beneath the right collar bone. 

After a meal containing fatty foods, the lymph in the 
thoracic duct changes from a clear, watery fluid to a 
milk-white color. This is due to the fact that the 
lymphatics of the villi take up the digested fats (or 
chyle), and carry them directly to the thoracic duct. As 
the digested fats are of a milky color, so the contents of 
the thoracic duct become of a like color ; this only lasts, 
however, while the chyle is being absorbed. All the other 
lymphatics are constantly filled with the colorless lymph. 

The Lymph Corpuscles. — Before the lymph enters the 
lymphatic glands it is clear and transparent, and free 
from corpuscles, but after passing through these glands 
the microscope shows that it contains a number of small 
round bodies called lymph corpuscles. Soon these cor- 
puscles mingle with the blood, when they are called the 
white blood corpuscles. Therefore we see that one source 
of the origin of the white blood corpuscles is the lymphatic 
corpuscles. 

Review. — Let us now trace the foods from the time 
they are taken into the mouth until they are absorbed. 
Take the three representative foods : lean meat, starch, 
and fat : — 

First, mastication, or chewing ; second, mixing with the 
saliva; third, swallowing; fourth, stomach digestion, for 
the proteid foods; fifth, intestinal digestion, for the fatty 
and starchy foods ; sixth, absorption, the proteid s and 
starches in the food being absorbed by the blood vessels, 
and the fatty foods by the lac teals. 

A study of Fig. 20 will aid in understanding and 
remembering the course pursued by the digested foods. 

Begin with the four villi at the right of the intestine : 



68 



THE ESSENTIALS OF HEALTH 




Fig. 20. — Diagram illustrating the course of 
the absorbed foods. A, intestine : (1) villi with 
central lacteals; (2) villi with blood vessels. 
B, lymphatic or lacteal vessels. C, lymphatic 
gland. D, thoracic duct. E, portal vein. F, 
liver, at the left of the figure. G,vein. H, heart. 
J, right auricle of heart. V, vein. 



suppose the central 
lacteals ?*re filled with 
chyle, or digested fats. 
The four lacteals unite 
to form a larger ves- 
sel, B, which passes 
through a lymphatic 
gland, C, and empties 
into the dilated begin- 
ning of the thoracic 
duct, D. The chyle 
then passes up the 
duct in the direction 
of the arrowheads, 
until it enters the 
large vein, shown in 
the diagram at V, 
which leads directly 
to the right side of 
the heart. Consult 
also Plate I, opposite. 
Suppose again that 
the blood vessels of 
the villi at the left 
(2) are filled with 
absorbed foods de- 
rived from the lean 
meats and starches. 
The vessels soon unite 
to form the portal 
vein, E, which car- 
ries the food directly 
to the liver, F. From 



Plate I. — Illustrating the action of the lymphatics; The upper diagram 
represents a cross section of the small intestine. The finger-like points (A) are 
the villi. The dark-colored line leading from each one represents a lacteal 
vessel. These minute vessels unite to make larger vessels as shown at (B). 
The network of vessels, colored red, represents the capillaries of the villi. 
These also unite to make larger blood vessels as shown at (C). 

The lower diagram illustrates the larger lymphatics or lacteals, of the 
intestines. The minute lymphatics (dark lines, upper diagram) unite, forming 
larger vessels and these unite forming still larger vessels, as at 1. These 
vessels then enter small lymphatic glands, (2), and after passing through these 
glands they terminate in the thoracic duct (3), this duct lies by the side of a 
larger vein, directly in front of the spinal column. Finally the thoracic duct 
opens into a large vein beneath the left clavicle. 





PLATE I. 



ABSORPTION 69 

the liver it can pass through the veins, in the direction 
of the arrowheads, to the right side of the heart. 

Parts of Food not Absorbed. — We have now traced the 
processes by which the food we eat is absorbed into the 
blood. We have also learned something of the marvelous 
way in which the food becomes changed into the various 
tissues of the body, nourishing them and building them up. 
But all the food that we eat cannot be so absorbed and 
changed, for part of it is not digestible, and what is not 
digested cannot be absorbed. 

To illustrate : The walls of the cells of all plants are 
composed of a substance called cellulose, which is indiges- 
tible. Again, there are some tissues in the various meats 
which are indigestible or are so difficult of digestion that 
they are frequently not acted upon by the digestive juices. 
It is also found that we often eat food which contains 
more nourishment than the body actually requires ; in 
such cases some portion of the food would remain un- 
digested, although under other conditions it might be 
digested. 

Waste must be Removed. — This undigested and waste 
material must be removed from the body or serious con- 
sequences would result. When we are in good health, 
and pay prompt attention to certain laws of health, nature 
attends to the carrying off of this waste material. It 
seems to be a natural law that at least once each day this 
material must be removed from the body if health is to be 
maintained. But we frequently overeat, eat too hastily, 
neglect proper exercise, or in some other way interfere 
with nature's method. This must always result in affect- 
ing the health more or less seriously. If you should ask 
a physician how important he thought it was to have this 
waste material removed from the body at least once each 



70 THE ESSENTIALS OF HEALTH 

day, he would probably tell you that a great many serious 
complaints begin from the failure of the body to dispose 
of this waste material. 

In the case of young people it is generally very easy to 
correct troubles of this kind by proper diet. Fruits are 
useful as laxatives, and especially such fruits as stewed 
prunes, figs, baked apples, peaches, and nearly all ripe 
fruits eaten raw. Eating such coarse foods as brown 
bread, graham bread, oatmeal, and cracked wheat is also 
beneficial. Nearly all vegetables, especially spinach, let- 
tuce, cauliflower, and celery will aid nature in the same 
way. If the suggestions given above do not produce the 
desired effect then it is better to consult a physician, even 
before you feel ill, in order that the condition may be 
easily corrected before it becomes habitual. 

The daily removal from the system of useless and waste 
material, through the action of the bowels, is of such great 
importance that it is absolutely necessary to good health. 



CHAPTER IX 
THE BLOOD 

Distribution of Blood. — The blood is very generally 
distributed through the body. There are a few parts in 
which it is not found, as in the hard parts of the teeth, 
the hair, the nails, the outer layer of the skin, some parts 
of the eye, and most of the cartilages. These parts are 
nourished by absorbing the fluids which escape from 
neighboring blood vessels. It is estimated that about one 
twelfth of the weight of the body is composed of blood. 

Medium of Exchange. — The blood receives a large 
amount of new material from the digested food, and a 
supply of oxygen from the air in the lungs. It carries 
these fresh supplies to the various organs and tissues, 
gives them up where they are needed, and receives in ex- 
change carbon dioxide and other products of waste. From 
this it is seen that the blood always contains both new 
and old material ; new material on its way to build up 
tissue, and old material on its way to the kidneys, the 
lungs, and the skin through which this worn-out matter 
is removed from the body. 

Composition of the Blood. — Blood appears to the un- 
aided sight as a thick, opaque, red fluid. But under the 
microscope it is seen to consist of two parts : a transparent, 
nearly colorless fluid, called the plasma ; and a large num- 
ber of minute bodies floating in the plasma, called the 
blood corpuscles. 

71 



72 



THE ESSENTIALS OF HEALTH 



The Blood Corpuscles. — The blood corpuscles are of 
two kinds, the white and the red. The white corpuscles, 
as their name indicates, are without color. They are 
spherical bodies, averaging about 2 5V0" °^ an ^ ncn ^ u diam- 
eter. They are a trifle larger than the red corpuscles, 
but not so abundant, the average number being one white 
corpuscle to about five hundred red ones, although this 
number is subject to variation even in health. The white 
corpuscles are capable of changing their form by a flow 
of their substance in various directions, after the manner 
A 







A 




b b b 



Fig. 21. Fig. 22. 

Fig. 21. — Human blood, highly magnified: A, the white corpuscles; the 
others shown are the red corpuscles; B, section of a corpuscle. 

Fig. 22. — Human blood, more highly magnified: a, a white corpuscle; 
the others shown are the red corpuscles; b, section of a corpuscle. 

of the amoeba, as illustrated in Fig. 2. They originate, as 
we have learned, from the corpuscles found in the lymph. 

The white blood corpuscles are known to have a very 
prominent part in the prevention of disease. It is claimed 
that these minute bodies are directly concerned in the 
destruction of germs which gain entrance to the body 
and which would cause severe diseases unless promptly 
destroyed. The white corpuscles quickly take these 
disease germs within their own bodies and there com- 
pletely destroy them. 

The red corpuscles of human blood are circular bodies, 




THE BLOOD 73 

slightly hollowed toward the center. Fig. 21 shows a 

number of these bodies, shaded in the center to give the 

correct impression that they are concave. One corpuscle, 

at the left of the figure, B, is seen on 

the edge, showing that it is biconcave, 

or slightly hollowed on each side. The 

red corpuscles exist in vast numbers. 

It is estimated that in a minute drop 

of blood there are over five millions of 

them; while in a medium-sized person 

there are not less than twenty-five 

billions, — too vast a number for the FlG 

mind to comprehend. The red cor- blood, highly magnified: 

puscles originate chiefly from the cells A ' the white «»■**»; 

L ° J . B, the nucleated, oval, red 

found in the marrow of bone. Fig. 22 corpuscles. 
represents a few red corpuscles and 

one white corpuscle, very highly magnified. (Compare the 
corpuscles in the blood of animals, Figs. 23, 24.) 

Function of the Red Corpuscles. — The most important 
ingredient of the red corpuscles is their coloring matter, 
called hemoglobin. This substance has a strong liking, 
an " affinity,'" for oxygen. So strong is this affinity that 
when the blood flows through the lungs, the coloring 
matter, or hemoglobin, takes oxygen from the air which 
it finds there. The red corpuscles thus become loaded 
with oxygen. The blood soon leaves the lungs, and flows 
to the most distant tissues, which are in great need of 
this oxygen. But the tissues exert a stronger affinity 
for the oxygen than does even the hemoglobin, and thus 
the latter is obliged to give up the oxygen. The red 
corpuscles are called the " oxygen carriers " ; for their 
great object is to carry oxygen from the lungs to all 
the various organs and tissues of the body. 



74 



THE ESSENTIALS OF HEALTH 




1 



Arterial and Venous Blood. — As soon as the red cor- 
puscles receive their fresh supply of oxygen in the lungs, 
they become bright red in color, making all the blood a 
/*x bright scarlet. This bright- 



colored blood is called arte- 
rial blood. It is found in 
the arteries, those vessels 
which carry blood from the 
heart to the distant tis- 
sues. In one place arterial 
blood is found in the veins, 
— the pulmonary veins, — 
which carry the blood from 
the lungs to the left side of 
the heart. 

When the blood is passing 
through the smallest ves- 
sels, it gives up its oxygen 
to the tissues. Deprived of 
its oxygen, the hemoglobin 
of the red corpuscles be- 
comes much darker in color, 
therefore all the blood looks 
darker. This darker-colored 




Fig. 24. — Showing the relative size 
of red blood corpuscles of different blood is Called venOUS blood 



animals: (1) musk deer; (2) horse; 
(3) mouse ; (4) man ; (5) whale ; 
(6) elephant; (7) humming bird; 
(8) pheasant ; (9) pigeon ; (10) snake ; 
(11) crocodile; (12) triton; (13) proteus. 



It is found in the blood 
vessels which carry the 
blood from the tissues back 
to the heart. It is also 
pulmonary artery, — which 



found in one artery, — the 
carries the blood from the right side of the heart to the 
lungs. The arteries generally contain the bright arterial 
blood, and the veins the dark venous blood ; but to this 



THE BLOOD 75 

rule there are the two exceptions already given, the pul- 
monary artery and the pulmonary veins. 

Oxygen and Carbon Dioxide. — The air we breathe con- 
sists principally of two gases, — oxygen and nitrogen. 
The oxygen is essential to all life. Without it, we should 
soon die. All parts of the body need it. The tissues 
are constantly demanding it, and countless numbers of 
red blood corpuscles are continuously and rapidly at 
work distributing it throughout the body. 

We know that a substance called carbon forms a 
part of all the tissues of the body. When the oxygen 
reaches the tissues, it unites with their carbon, forming 
carbon dioxide. This is a poisonous gas, and the body 
must cast it off as soon as possible ; therefore it mingles 
with the plasma of the blood and is soon carried to the 
lungs, where it escapes from the body. 

Arterial and Venous Blood Compared. — From what has 
been said we are able to place in a more concise form the 
differences between arterial and venous blood : — 

Arterial blood contains the more oxygen. 

Venous blood contains the more carbon dioxide. 

Arterial blood is of a bright scarlet color. 

Venous blood is of a darker, nearly purplish red. 

Arterial blood parts with its oxygen in the capillaries. 

Venous blood parts with its carbon dioxide in the lungs. 

Arterial blood contains substances for the nutrition of 
the tissues. 

Venous blood contains the worn-out materials from the 
tissues. 

Coagulation. — Soon after blood has escaped from a 
blood vessel, it thickens to a jelly-like mass. This is 
called the coagulation, or clotting of blood. Blood never 



76 



THE ESSENTIALS OF HEALTH 



clots while in the blood vessels of the living body, unless 
some disease or some unusual condition be present. It is 
one of the wise provisions of nature, however, that coagu- 
lation takes place whenever a blood vessel is cut or 
wounded, thus preventing possible bleeding to death. 
The lower animals may be severely bruised and wounded, 
or may even lose a portion of a limb, laying bare large 
blood vessels, without fatal results. This is because the 
blood soon clots, forming a solid mass at the openings of 
the vessels and preventing any further escape of blood. 





Fig. 25. — A bowl of recently 
coagulated blood ; the clot is of 
uniform density. 



Fig. 26. — The same bowl of blood a 
few hours later ; the clot is contracted 
and floats in the liquid serum. 



Whenever any vessel of considerable size in the human 
body is ruptured, it is advisable to aid nature by checking 
the flow of blood for a short time, in order that the clot 
may be well formed. This is accomplished by pressing on 
the part, which any one of us could do, or by placing 
a fine thread around the ends of the ruptured vessel ; 
this must be done by a surgeon. 

The clotting of the blood is due to the change of some 
of its liquid elements into a substance called fibrin. Fibrin 
consists of innumerable delicate fibrils, so minute that they 



THE BLOOD 77 

are seen only with the higher powers of the microscope. 
The fibrils are like so many minute threads, which en- 
tangle the blood corpuscles and form with them a soft, 
semifluid mass. In a few moments after blood has been 
exposed to the air, it begins to change, as has been stated, 
to a jelly-like mass. Later the mass begins to contract, 
while there escapes from it a clear fluid, called the serum. 
Still later the central mass becomes quite hard, so that it 
may be cut with a knife. This central hard mass is known 
as the clot, and consists of the fibrin and the corpuscles ; 
while the serum represents the other constituents of the 
blood. (See Figs. 25 and 26.) 

The Spleen. — The spleen is a small organ of less than 
one half pound in weight. It is situated to the left of 
the stomach, and is directly concerned in the formation 
of the blood corpuscles, both the white and the red. 



CHAPTER-X 



THE CIRCULATION 



We have learned that new material, absorbed from the 
digested food, must be carried to all parts of the body, 
for its proper nourishment; and we have also learned 
that old or useless material must be removed from the 

body. This process of 
repair and waste is con^- 
stantly going on ; and the 
blood is the great circu- 
lating medium through 
which these changes take 
place. 

There are four different 
parts to be studied in con- 
nection with the circula- 
tion of the blood, — the 
heart, the arteries, the 
capillaries, and the veins. 
The Heart. — The heart 
is a large hollow muscle placed obliquely in the chest 
cavity between the lungs. It weighs from ten to twelve 
ounces and measures about five inches in length. It is 
conical in shape, with the apex of the cone pointing down- 
ward, forward, and to the left. The location of the apex 
can be easily determined by placing the hand over the left 
side, and feeling the strokes against the walls of the chest. 

78 




Fig. 27. — The position of the heart. 



Plate II. — Showing the general plan of the circulation: The arrows in- 
dicate the direction in which the blood flows. The purification of the blood 
in the lungs (1, 2) is suggested by the difference in coloring between the dark- 
red, impure blood, as it enters the lungs from the right side of the heart (3) 
and the bright red, purified blood which is carried from the lungs to the left 
side of the heart (4) ; The purified arterial blood then passes into the aorta, 
some of it leaving through the branches, (5, 8) to supply the upper extremities; 
and through the branches (6, 7) to supply the head. The purified blood also 
passes down the abdominal aorta (13) to supply the trunk and lower 
extremities. 

The impure venous blood returns to the right side of the heart, from the 
upper extremities, through the veins (9, 12) and from the head through (10, 11). 
From the trunk and lower extremities it returns through the large vein (14). 



^Il 1 we 




THE CIRCULATION 



79 



The apex has considerable freedom of motion, while the 
base, or upper end of the heart, has but little motion. 

A reference to Fig. 27 shows that the heart is not all 
on the left side of the body. It extends about three 
inches to the left of the 
median line, and an inch 
and a half to the right of it. 

The Pericardium. — The 
heart is completely sur- 
rounded by a sac or mem- 
branous bag, called the 
pericardium, the lower part 
of which rests on the dia- 
phragm. The cells which 
cover the inside of the peri- 
cardium secrete a watery 
fluid which keeps its inner 
lining very smooth and en- 
ables the heart to move 
against it without friction. 

Cavities of the Heart. — 
The heart is divided length- 
wise by a firm muscular 
wall. There is no opening 
in this wall, hence there is 
no connection between the 
two sides of the heart. One side, the left, always contains 
arterial blood ; and the other side, the right, venous blood. 

Each side of the heart is also divided into two parts 
by a wall, which, in this case, is placed crosswise. But 
this cross wall is not complete ; there is an opening in it, 
so that the blood freely passes from the upper part to the 
lower part. This opening is protected by valves which 




Fig. 28. — Tiie heart and the larger 
vessels at its base or upper part : (1) 
and (2) veins ; (3) right auricle ; (4) 
right ventricle ; (5) pulmonary artery ; 
(6) pulmonary veins ; (7) left auricle ; 
(8) left ventricle; (9) aorta; (10) 
branches from the aorta. 



80 



THE ESSENTIALS OF HEALTH 



do not allow the blood to pass in the other direction. 
Thus there are four cavities in the heart. 

The two upper cavities are called auricles, from their 
fancied resemblance to ears; the two lower cavities are 
called ventricles. Each side of the heart consists of an 
auricle above and a ventricle below. All these cavities 
are lined with a very- smooth membrane. 

A careful study of Fig. 28 will lead to a better under- 
standing of these divisions of the heart. The right side 

of the heart is represented 
at (3) and (4), while (7) 
and (8) represent the left 
side. The firm muscular 
wall which divides the heart 
lengthwise is directly be- 
neath the small bloodvessel 
shown on the outside of the 
heart, to the left of the 
number (8). The right 
side of the heart is here 
represented as composed of 
an auricle at (3) and a 

Fig. 29. —A diagram illustrating ventricle at (4). The left 

the flow of blood through the heart: gide of the heart j g nearl 

(1) and (2) veins ; (3) right auricle ; . J 

(4) right ventricle ; (5) pulmonary ar- hidden from view, but a 

tery ; (6) pulmonary veins ; (7) left p ar t of its auricle (7) and 

auricle; (8) left ventricle ; (9) aorta. «.. . .' -. , ON " t 

of its ventricle (8) can be 
seen. At (1) and (2) are represented the veins which 
carry the blood from the distant parts of the body to the 
right side of the heart. The largest artery in the body, 
which is called the aorta, is shown at (9). 

The Contractions of the Heart. — Since the heart is a 
muscle, it has the power of contracting. When the 




THE CIRCULATION 81 

auricles contract, the blood is forced into the ventricles. 
As soon as this occurs the ventricles contract, forcing the 
blood out into the arteries. The flow of the blood is 
always onward, because there are valves that prevent its 
setting back into the heart. Such valves are found be- 
tween the auricles and the ventricles, and also between 
the ventricles and the arteries. 

The Course of the Blood. — In tracing the course of the 
blood through the body, we might start anywhere in the 
circulatory system because, as the heart is always pump- 
ing, and the blood is always flowing, there is no beginning 
point. But, to follow the round, let us imagine that the 
. left ventricle of the heart, Fig. 29 (8), has contracted, 
forcing the blood into the large artery (9). The blood 
then travels through this artery into the many branches 
which lead out from it ; these branch arteries grow smaller 
and smaller until finally they join the still finer blood 
vessels called capillaries. The capillaries are very small 
tubes which go to every part of the body. In them the 
blood flows more slowly and is brought into contact with 
the individual cells. It is here that the blood gives to 
the tissues the nourishment that it carries, and here the 
materials that the tissues have worn out in doing their 
work are given off to the blood. From the capillaries 
the blood, now carrying the impurities it has taken up, 
passes into somewhat larger vessels which the capillaries 
unite to form. These are the veins, and they increase in 
size as one joins another, making larger and larger veins 
— finally all the veins unite into two large veins, Fig. 
29 (1) (2), which carry the now impure blood back 
to the heart again and pour it into the right auricle. 
After this auricle becomes filled, it contracts and forces 
the blood in the direction of the arrowheads into the 



82 THE ESSENTIALS OF HEALTH 

right ventricle (4). When the ventricle is filled, it con- 
tracts and forces the blood in the direction of the arrow- 
heads into the pulmonary artery, through which it is 
carried to the lungs. 

This dark blood then flows through the lungs, giving 
off its carbonic acid gas there and receiving a fresh 
supply of oxygen. This is illustrated in Plate II. After 
passing through the lungs, it enters the pulmonary veins 
(6) as bright, purified, arterial blood. These veins carry 
the blood to the left auricle (7), which contracts, as did 
the right auricle, forcing the blood into the left ventricle. 
From there it starts on another course through the body, 
such as we have just traced. 

This description of the blood's travels is necessarily 
incomplete, and will need some correction if taken too 
literally. While the general course of the blood is the 
same, we must not get the notion that it all travels the 
same path, or that it all makes the entire circuit of 
the body. For instance, the blood that goes at any one 
moment from the heart to the arteries in the shoulder 
naturally makes its trip quicker and returns again through 
the veins to the heart earlier than the blood does that 
starts at the same time through the blood, vessels that go 
to the feet. 

The Left Ventricle Stronger than the Right. — The left 
ventricle has to contract with force sufficient to send the 
blood to the most distant parts of the body ; while the 
right ventricle has to send the blood only to the lungs, 
which are but a short distance from it. Therefore, we 
find that the muscular walls of the left side of the heart are 
much thicker and stronger than those of the right side. 

The Beating of the Heart. — The throbbing movement 
of the heart is called the beat of the heart. It is subject 



THE CIRCULATION 83 

to much variation and is involuntary. In man, the heart 
beats about 70 times per minute ; in woman, about 80 
times per minute. This average may be greatly increased 
for a short time by many circumstances, as by violent ex- 
ercise or excitement ; but if the increase be long continued, 
it denotes some disturbance of the system. If the heart 
beats continuously 150 or 160 times a minute, the condition 
indicates great danger. Serious trouble is also generally 
indicated when the heart beats less than the normal num- 
ber of times. The heart beat varies greatly with the age. 
At birth it is about 130. It gradually falls until at three 
years of age it is about 100 ; at fourteen, about 80 ; and 
at twenty-one, about the average for the adult. 

Exercise of all kinds accelerates the beating of the 
heart. Even the muscular effort of standing increases its 
rapidity. The heart beats are about ten more per minute 
when one is standing than when one is lying down. When 
one runs and jumps, the heart beats faster. Hence if, in 
taking violent exercise, the heart begins to beat too rap- 
idly, one can usually relieve it by lying down. Any 
sudden excitement, as fright, will cause the heart to beat 
violently, so that it is felt to strike with much force against 
the walls of the chest. Excessive fear, joy, or grief may 
also have an effect on the nervous system powerful enough 
to cause the heart's action to cease, producing instant 
death. Sorrow and depression of spirits may cause the 
number of beats to be reduced. Taking the seasons 
through, we are told that the heart beats faster in summer 
than in winter. 

The Heart Works and Rests. — The heart does an im- 
mense amount of work. At the rate of seventy beats 
per minute, there are a hundred thousand contractions 
daily. The labor expended by the heart each day is 



84 THE ESSENTIALS OF HEALTH 

equal to the force required to lift one hundred and twenty 
tons a foot from the ground. 

If the heart does such an amount of work, it must 
have rest. We find there is a period of time when it is 
completely at rest. The auricles contract together ; im- 
mediately after, the ventricles contract, also ; and follow- 
ing their contraction there is a period of complete rest, 
after which the auricles contract again. Brief as this 
period is, it yet represents about one fourth of the time 
of a whole beat. From this it is seen that the sum of 
all these brief periods of rest is in a whole day not less 
than six hours. 

The Sounds of the Heart. — If we listen to the heart 
beats, by placing an ear over the heart, two distinct 
sounds are heard, one immediately following the other. 
After an instant of silence they are repeated. It is no- 
ticed that these two sounds correspond with each beat of 
the heart. The first sound is comparatively long and 
dull ; the second, almost immediately following it, is 
sharper, shorter, and more distinct. The sounds are 
likened to those produced by pronouncing the words 
tubb, dup. 

The first sound is caused (1) by the sudden closure of 
the valves which are between the auricles and the ven- 
tricles, together with (2) the sound caused by the power- 
ful contraction of the muscular walls of the ventricles. 
The first sound is, therefore, a valve sound and a muscle 
sound. The second sound is caused by the sudden closure 
of the valves which are at the beginning of the pulmonary 
artery and the aorta. It is, therefore, entirely a valve 
sound. 

The Pulse. — The pulse is a throbbing pressure corre- 
sponding to the beat of the heart. It may be felt at the 



THE ClUCULATIOX 



85 



radial artery near the wrist, at the temporal artery over 
the temples, and in other places. The pulse is caused 
by the contraction of the 
ventricles, and the conse- 
quent expansion of the 
arteries. For instance, 
each contraction of the 
heart suddenly forces a 
quantity of blood into 
the arteries. The walls 
of the arteries expand to 
accommodate the extra 
amount of blood thus 
forced into them, and this 
expansion is felt near the 
wrist as the pulse. When 
the heart relaxes, the ar- 
teries would force the 
blood back into it, were 
it not for the closure of 
the valves, which fully 
prevent any backward 
flow. As the blood can- 
not go in a backward 
direction, it is pushed 
forward under the pres- 
sure of the elastic walls Fig. 30. — The general plan of the circula- 
of the arteries. Thus tion ' (See PP . 86 and 87.) 

the arteries relieve themselves of the excess of blood, 
so that their walls do not remain so fully distended. But 
no sooner have the arteries returned to their former 
size than they are again expanded by another contraction 
of the heart. This constant series of expansions of the 




86 THE ESSENTIALS OF HEALTH 

arteries gives rise to the pulse, which is present in all 
arteries. Therefore each arterial expansion, or each pulse, 
represents a contraction of the ventricles. The pulse thus 
becomes a guide for ascertaining the frequency and regu- 
larity of the heart's action, and the condition of the gen- 
eral circulation. 

As nearly all the arteries are deep-seated, only those 
few near the surface, as mentioned above, are used to 
study the pulse. It is possible to seethe pulsations of an 
artery with the unaided eye, such pulsations showing at 
times on the temple, on the neck, or at the wrist. 

The Arteries. — The arteries, as we have seen, are the 
vessels which carry the blood from the heart to the various 
parts of the body. They are firm tubes, the Avails of 
which are composed of elastic and muscular tissue. The 
muscle is of the involuntary variety, and the walls are so 
arranged in the tube as to give the artery the power of 
expanding and of contracting so that it can accommodate 
itself to the amount of blood it contains. The largest 
artery in the body is the aorta, which is nearly an inch in 
diameter. It is the great central artery of the body. If 
an artery is cut across it will retain its circular form 
because of its elastic and muscular walls. After repeated 
divisions of the arteries, they become very small, so that 
they can only be seen with the highest powers of the 
microscope. 

Names of Principal Arteries. — In Fig. 30 we have a diagram of the 
general plan of circulation. The darker lines represent the arteries, 
which carry blood away from the heart, the lighter lines represent the 
veins, which carry blood toward the heart. The numbering here 
given corresponds with that on Plate III. (3) Carotid arteries, one 
for each side of the neck. The beat of these arteries may generally 
be felt by placing the fingers on the side of the neck. These arteries 
carry the blood to the head. (6) Large arteries beneath the clavicle. 




PLATE III 

The general plan of circulation, and the names of the principal arteries : 
D, diaphragm; H, heart; A, abdominal aorta; (1) the aorta; (2) arch of 
the aorta; (3) the carotid; (4) the external carotid, supplying- blood to the 
outer surface of the head; (5) the internal carotid, to brain and eyes; 
(f>) the subclavian, situated beneath the clavicle; (7) the axillary, in the 
axilla or armpit; (8) the brachial, lying along the inner side of the arm; 
(9) the radial, on the radial side of the forearm ; (10) the ulnar, on the ulnar 
side of the forearm; (11) the hepatic, to the liver; (12) the gastric, to the 
stomach ; (13) the splenic, to the spleen ; (14) the superior mesenteric, to the 
small intestines and a portion of the large intestine ; (15) the renal, to 
the kidneys ; (16) the inferior mesenteric, to a portion of the large intestine ; 
(17) the common iliac, a division of the aorta; (18) the femoral. 



88 



THE ESSENTIALS OF HEALTH 



As each of them extends down the under side of the arm it is called 
the brachial artery. At the elbow it divides into two arteries, one by 
the side of the radius being called the radial artery, and the other 
at the side of the ulna being called the ulnar artery. (L) Arteries 
of the lungs. (A) Continuation of the aorta. When the aorta reaches 
the abdomen, as here illustrated, it is called the abdominal aorta. At 
this point are seen three branches from the abdominal aorta; one 
supplying the liver, another the spleen, and another the stomach. 
(17) When the abdominal aorta reaches the lower part of the abdomen 
it divides into two large arteries, one for each leg. When each of the 
divisions reaches the thigh it is called the femoral artery, because it is 
by the side of the femur. (15) Arteries which supply the kidneys (K). 



The Capillaries. — When an artery has become so small 
that even the muscular and elastic coats have disappeared, 

and only the thin lining 
membrane is left, it is 
called a capillary. We 
have traced the blood 
current through the ar- 
teries into these most 
minute blood vessels, the 
capillaries, which pene- 
trate t*he organs and tis- 
sues of the body. We 
have found that here the 
blood is brought into 
very close contact with 
the cells of the tissues ; 
for between the living 
tissues and the blood in a capillary, there are but two 
of the thinnest membranes. Many of the capillaries are 
so small that when the blood flows through them, the 
corpuscles, tiny as they are, have to pass in single file, as 
there is not room enough for them side by side (Fig. 31). 




Fig. 31. — A, a small artery ; C, capillaries ; 
V, a small vein, magnified. 



THE CIRCULATION 



89 





The Veins. — The capillaries in turn unite with each 
other to make larger vessels, which are called veins. The 
veins convey the blood \ \ / / 

from the capillaries \\ / f \n 

to the heart. The 
smaller veins unite to 
make larger ones, un- 
til at last the large 
veins are formed 
which empty into the 
right auricle of the 
heart. The walls of 
the veins are much 
thinner and less elas- 
tic than the walls of 
the arteries. 

Nearly all the veins 
have valves to prevent the backward flow of the blood. 
This is illustrated in Figs. 32 and 33. It is evident that 
if the blood flows in the direction of the arrowhead, in 
Fig. 32, the valves will remain open, but if it should at- 
tempt to flow in the opposite direction, as in Fig. 33, the 
valves would close and completely shut off the passage. 

Generally speaking, the veins are placed side by side 
with the arteries, and have corresponding names. The 
large vein by the side of the aorta is called the inferior 
vena cava. 

Rapidity of the Circulation. — The blood nearest the heart, 
in the aorta, flows the most rapidly, because all the force 
of the heart's contraction makes itself felt here. As the 
arteries divide, the stream becomes less rapid until in 
the capillaries it is much slower. It is estimated that the 
blood near the heart flows five hundred times faster than 



Fig. 32. — The valves Fig. 33.— The valves 
of a vein, open. of a vein, closed. 



90 THE ESSENTIALS OF HEALTH 

it does in the capillaries. In the large arteries near the 
heart, the blood flows at the rate of about a foot per 
second. In the veins the flow is not so rapid as in the 
arteries, but is more rapid than in the capillaries. A 
quantity of blood can leave the heart, make a complete 
round of the body, and reach its starting place again in 
less than half a minute. 

It is impossible to show in any diagram the marvelous 
intricacy of the circulation of the blood ; through which, 
as we have learned, all the different parts of the body are 
fed, and are also, as we shall soon learn, purified. Still 
Plate IV may be very helpful to us in the effort to picture 
these wonderful operations. It is intended to suggest 
the connections and relations of the different parts of the 
system, but is by no means an exact illustration of 
the process as it takes place in any one part. 

Aids to the Circulation. — The heart itself is capable of 
contracting with sufficient force to send the blood on its 
complete round of the circulation. But there are many 
aids to this force. Exercisers one of the most important. 
It not only causes the heart to beat faster and thus has- 
tens the flow of blood, but it is a direct aid to the move- 
ment of blood in the veins. When a vein is filled, the 
blood cannot flow backward toward the capillaries on ac- 
count of the valves ; therefore, if the muscles be made to 
contract and thereby press upon the veins, the blood will 
be pushed onward faster. When the muscles relax, the 
vein is again filled with blood coming from the capillaries. 
More muscular exercise will again hasten on the blood to 
the heart. 

Very tight clothing is a hindrance to the circulation. 

Effects of Alcoholic Drinks on the Circulation. — The 
habitual use of alcoholic drinks is often a cause of heart 



Plate IV. — A diagram of the circulatory system intended to show the 
manner in which the blood travels through the body. In the lungs (1), the 
blood is purified as shown in the change from dark red to light red. the blood 
leaves the lungs through the pulmonary veins (2), through which it enters the 
left auricle of the heait (3); the purified blood then passes into (4), the left 
ventricle; then out into the arteries represented by (5) ; then into the capil- 
laries represented by (6); then into the veins (7); and back to the right auricle 
of the heart (8); to the right ventricle (9); through the pulmonary artery (10); 
to the lungs again, for purification. 

Note that the short circuit from the heart to the upper part of the body is 
illustrated by (5) (6) ■ (7), at the top of the figure, and the longer circuit by 
(5) (6) (7) at the bottom of the figure. 

There are also represented the capillaries of the liver (11), the spleen (12), 
the alimentary canal (13), and the kidneys (14). 




PLATE IV. 



THE CIRCULATION 91 

disease. The muscles of the heart become thickened and 
the cavities enlarged. A process of degeneration begins. 
Particles of fat, or oil, take the place of the muscle. At 
first, this is very slight ; but gradually much of the worn- 
out muscle disappears and fatty tissue takes its place. 
Physicians call this trouble " fatty degeneration of the 
heart." The heart becomes weaker and weaker, until, sud- 
denly, it is unable to do its work longer, and death occurs. 

It is not necessary that the strongest drinks be used to 
produce these changes. The extra amount of flesh found 
in those who use ale and beer freely is of this fatty nature ; 
and a fatty heart is what we should expect to find in such 
a fleshy body. 

Changes of like nature may also take place in the mus- 
cular tissue of the walls of the arteries. The cells become 
weakened by the deposit of fat within them, and the walls 
of the arteries lose some of their strength. This makes 
the walls more liable to rupture, and is one of the predis- 
posing causes of apoplexy. 

Alcohol and the Smaller Vessels. — The walls of the 
smaller arteries consist largely of muscular tissue. This 
tissue is kept continuously in a partially contracted con- 
dition, in order that the walls may be more firm. The 
muscular tissue is under the control of minute nerves. 
These nerves are capable of making the muscle contract 
firmly, thereby diminishing the size of the vessel ; while 
if they cease to act, from any cause, the muscle relaxes 
and the size of the vessel is greatly increased. 

The small arteries are said to have " tone " when these 
nerves exert their power, and keep the muscle in its usual 
condition of moderate contraction. The walls of the 
smaller arteries, therefore, are normally in a state of 
moderate contraction. The effect of alcohol is partially to 



92 THE ESSENTIALS OF HEALTH 

paralyze the center that controls the muscular tissue, so 
that it ceases to exert its full power. If a small dose 
of an alcoholic beverage be taken, the effect may be slight 
and only temporary, as illustrated in the flushing of the 
face ; if not repeated, recovery may be complete ; but a 
continuation of such doses causes the paralysis to become 
more permanent, and the nervous system to lose its power 
of controlling the size of the blood vessels. 

Not only the red nose and the red eyes of the confirmed 
drinker, but the reddened face and distended capillaries 
often seen in the moderate drinker, are indications of the 
paralysis of these little nerves. The " tone " has disap- 
peared from the walls of the blood vessels ; the muscular 
tissue is becoming or has become permanently relaxed, 
and the vessels are constantly in a distended condition. 
But the nose, eyes, and other portions of the face are not 
the only places where this congestion occurs. It exists in 
the mucous membranes of the body to a large extent ; 
while many of the organs and tissues are also in this 
chronic congested condition. 

Professor G, Sims Woodhead of Cambridge University, says: " Alco- 
hol is said to have a stimulating effect on the heart muscle. If its 
effect on the heart muscle is in any way similar to that exerted by it 
on the voluntary muscles, the effect is merely temporary, and is fol- 
lowed by a period of depression, during which the muscle does so 
much less work that there is a considerable falling off in the amount 
of work done, the greater the preliminary stimulation the greater the 
amount of falling off in later periods." 

Dr. Edward L. Fox, in an annual address, as president of the Brit- 
ish Medical Association, said, " It [alcohol] not only fails in giving 
power in the work of the muscles of the heart, but acts distinctly as a 
depressant." 

Tobacco and the Heart. — Tobacco affects the heart 
largely through the action of the nicotine on the nervous 



THE CIRCULATION 93 

system. A prolonged use of tobacco frequently gives rise 
to a particular affection known as the " tobacco heart." 
The author has seen a strikingly large number of these 
cases in young men between fifteen and twenty years of 
age. The heart is irregular in its action and sometimes 
beats with great force. This is often accompanied with a 
sensation of weakness or of great anxiety. There are 
occasional attacks of dizziness, shortness of breath, nausea, 
and vomiting. At times there is intense pain in the region 
of the heart. Tobacco will not make as serious changes 
in the structure of the heart as those caused by alcohol, 
yet it is capable of doing immense harm. 

Dr. A. Clinton of San Francisco, physician to several boys' schools, 
says : " A good deal has been said about the evils of cigarette smok- 
ing, but not one half the truth has ever been told. Cigarette smoking 
first blunts the whole moral nature. It has an appalling effect upon 
the physical system as well. It first stimulates and then stupefies the 
nerves. It sends boys into consumption. It gives them enlargement 
of the heart, and it sends them to the insane asylum. I am often 
called in to prescribe for boys for palpitation of the heart. In nine 
cases out of ten this is caused by the cigarette habit. I have seen 
bright boys turned into dunces, and straightforward, honest boys 
made into miserable cowards by cigarette smoking. I am speaking 
the truth, nearly every physician and nearly every teacher knows." 

Dr. H. A. Caley, writing in the Lancet, June, 1899, said : " In 
strict training just those agents and influences are eliminated which 
either directly or indirectly depress the heart and interfere with its 
muscular vigor — as, for example, alcohol and tobacco. They are 
avoided when the heart is to be driven at high pressure." 

There have been instances among our most prominent 
statesmen, where death w r as instantaneous, as a result of 
disease of the heart from the long-continued use of tobacco. 
With such a history tobacco should no longer be regarded 
as a luxury, but rather as a slow poison capable of accom- 
plishing an enormous amount of damage. 



CHAPTER XI 
RESPIRATION 

Respiration. — The function by which oxygen is intro- 
duced into the body, and carbon dioxide is removed from 
it, is called respiration. 

Ordinary respiration is involuntary. We breathe when 
we are not thinking of it, and breathe as regularly when 
asleep as when awake. But respiration is also partly 
voluntary, for it is possible to breathe for a short time 
more slowly or more rapidly than usual. By taking 
advantage of this fact, the respiratory muscles can be 
greatly strengthened. 

A Lung Exercise. — Raise the arms slowly from the sides, 
at the same time drawing a long, deep breath. Then let 
the arms gradually fall while you blow the air out slowly 
through the mouth. This exercise will change the air in 
the lower part of the lungs, strengthen the lungs them- 
selves, and increase their capacity. All this aids greatly 
in maintaining the general health and that of the lungs. 

Crying and laughing are voluntary respiratory move- 
ments, principally spasmodic contractions of the diaphragm. 
Even these movements may become involuntary; the spas- 
modic, action of the diaphragm may go beyond the indi- 
vidual's control, so that for a time it is impossible to cease 
laughing or crying. 

Number of Respirations. — The number of respirations 
should be about one to every four beats of the pulse. As 

94 



RESPIRATION ( .».) 

the average pulse of the male adult is about seventy, so the 
number of respirations should be about eighteen. But this 
is influenced by many conditions; as, the size of the lungs, 
the condition of the air, by exercise, singing, speaking, 
and other circumstances. The number cannot, however, 
be lowered for any considerable length of time ; the 
demands of the system for more oxygen and for an escape 
of the carbon dioxide are so great that it is impossible to 
resist them. 

The Nasal Cavities. — The nostrils are the proper chan- 
nels through which the air should reach the lungs. The 
nose has at least three important functions to perform in 
connection with respiration : these are to warm, to moisten, 
and to filter the inspired air. 

The first of these is evidently very important ; for if 
the cold air of winter should be brought directly in con- 
tact with the tissues of the throat, inflammation would 
be likely to follow, causing sore throat, hoarseness, and 
loss of voice. The tissues of the nasal cavities are so well 
supplied with blood that they are capable of warming the 
air as it passes over them, until its temperature more 
nearly equals that of the body. 

The second function is likewise important : there is at 
least a pint of liquid secreted every twenty-four hours by 
the mucous membrane lining the nose ; the air we inhale 
passes through the nose, takes up this moisture, and 
becomes saturated with it. That the air takes moisture 
from the tissues is easily proven by breathing through the 
mouth for a short time. As we breathe in this way, we 
find that the throat soon becomes dry, and swallowing is 
difficult. 

The third function is much like that of a filter. The 
cells covering much of the lining membrane of the nose 



96 THE ESSENTIALS OF HEALTH 

are supplied with little hairlike processes. These fine 
processes, or " cilia," catch the particles of matter found 
in dust and smoke, and in the ordinary air breathed in. 
In this way the nose acts as a filter. 

Mouth Breathing. — When breathed through the mouth, 
the air is but little warmed, is only slightly moistened, 
and is not filtered. Mouth breathing brings the air into 
contact with the larynx, trachea, and bronchial tubes, 
scarcely changed. It is still cold, dry, irritating, and, as 
a result, produces more or less inflammation. Inflamma- 
tion of the throat, enlarged tonsils, chronic hoarseness, and 
coughs are some of the affections which result from the 
pernicious habit of breathing through the mouth. Nature 
intended that we should breathe through the nose, and a 
number of evils will result if we fail in so doing. If it be 
impossible to get air through the nose, a physician should 
be consulted, that the difficulty may be removed. Early 
attention to these conditions would do much to prevent 
the catarrhal affections so prevalent in this country. 

Presence of Adenoids. — If a child is forced to breathe 
with the mouth open, then something is wrong, and a 
physician should be consulted in order that the trouble 
may be promptly remedied. Often the obstruction in the 
nose is due to the presence of growths called adenoids. 
These growths are in the back part of the passages of 
the nose ; they greatly interfere with speech, are often 
the cause of deafness, and if allowed to remain may be the 
cause of an unpleasant change in the countenance. They 
are injurious to health and should always be promptly 
removed as soon as their presence is determined. 

The Larynx. — After the air breathed in has passed 
through the nose, it passes down the throat, until about 
opposite the base of the tongue. Here it enters the upper 



RESPIRATION 



97 



part of the larynx, which is the organ of voice. This is 
situated at the upper and front part of the neck, and can 
be felt as a hard lump, more prominent in men than in 
women, commonly known as " Adam's apple." The larynx 
is about an inch and a half long and an inch in diameter. 
It is composed of cartilages, lined with mucous membrane. 
In about the middle of its interior are two strong bands of 
elastic tissue, called the vocal cords, by means of which we 
are able to make sounds. These cords extend from the 
front to the back of the cavity of the larynx. The space 




Fig. 34. — The position of the vocal 
cords daring inspiration: the rings of 
the trachea are seen between the vocal 
cords. VC, vocal cords ; E, epiglottis. 




Fig. 35. — The position of the vocal 
cords when uttering a high note : 
VC, vocal cords; E, epiglottis. 



between them, through which the air passes, is called the 
glottis : this opening varies in size according to the tension 
of the vocal cords. This is well illustrated by referring to 
Figs. 34 and 35. When we breathe, the vocal cords are 
quiet, and the opening between them is large, as in 
Fig. 34 ; but when sounds are produced, the vocal cords 
come together and the glottis is narrowed. The "pitch" 
of the voice depends upon the length of the vocal cords ; 
the longer cords producing the lower tones. For this 
reason, the voice is shrill in children, and usually higher 
in women than in men. The boy's larynx grows rapidly 



98 



THE ESSENTIALS OF HEALTH 




at twelve or fourteen years of age, causing the voice to 
" break " easily, and gradually to change to a lower pitch. 
The Epiglottis. — The entrance to the larynx is pro- 
tected by a valve called the epiglottis. During respiration, 

the epiglottis is directed 
upward, so that the larynx 
is open ; but during the act 
of swallowing, the epiglottis 
shuts tightly down over the 
larynx, preventing the en- 
trance of any solid or liquid. 
Occasionally, however, a 
particle of food, on its way 
to the oesophagus, "goes the 
wrong way " and slips into 
the larynx, when a violent 
cough is necessary for its 
removal. Study Fig. 36. 

The Trachea. — The tra- 
chea, commonly known as 
the windpipe, is continuous with the lower part of the 
larynx ; it consists of a number of rings of cartilage. The 
rings are placed one over the other, separated only by a 
narrow membrane. They keep the trachea from collapsing, 
thus always insuring a free passage for the air. The tube 
is lined its whole length with a mucous membrane. Just 
after entering the chest, the trachea divides into two 
branches, called the bronchi, one branch going to each lung. 
The Bronchi and the Air Cells. — After entering the 
lungs, the bronchi divide again and again, until they are 
very minute in size. They are everywhere lined with a 
mucous membrane. A study of Fig. 37 will make these 
facts more clear. Note the bronchial tubes, shown iri 



Fig. 36. — The upper air passages, 
and their relation to surrounding 
structures : (1) the mouth ; (2) the 
pharynx; (3) the uvula; (4) the epi- 
glottis ; (5) the tongue ; (6) the nasal 
passages ; (7) the larynx ; (8) the oesoph- 
agus. 



RESPIRATION 



99 



the right lung (4). There are also similar tubes in the 
left lung (5), but they are not visible in the figure. 
After these tubes have become very small, from their 
repeated divisions, they terminate in a collection of mi- 
nute sacs, called air cells. The walls of these air cells are 
very thin and highly elastic. Fig. 38 shows a terminal 
bronchial tube with its air cells. If we bear in mind that 
these air cells have elastic walls, it is easy to imagine 
how they could be inflated, 
like so many rubber sacs, by 
forcing air into the tube, 
at (1). This is practically 
about what occurs when we 
draw in an ordinary breath. 

The inner surface of these 
air cells is exposed to the 
air which enters the lungs. 
The amount of surface thus 
exposed is very great, being 
estimated to be at least four- 
teen hundred square feet. 
Surrounding the outer walls 
of the air cells is a dense 
network of capillary blood 
vessels. Thus the blood itself is separated from the air 
only by the thin wall of the blood vessel and the fine mem- 
brane of the air cell. It is here, in the air cells, that the 
changes occur which transform the dark venous blood into 
the bright arterial blood. 

The Lungs. — The two lungs are situated in the tho- 
racic cavity, one in each side of the chest. Owing to 
the amount of elastic tissue in the air cells, the lungs 
have great power of expansion. When removed from the 

LOFC. 




Fig. 37. — (1) The epiglottis ; (2) the 
larynx; (3) the trachea; (4) the right 
lung ; (5) the left lung. 



100 THE ESSENTIALS OF HEALTH 

body, they appear completely collapsed ; still they float 
in water on account of the air yet remaining in the air 
cells. When in this collapsed condition, if a tube be 
placed in the trachea, the lungs may be inflated by blow- 
ing or by forcing air into the tube. After the inflation, it 
is only necessary to remove the tube, or allow the air to 
escape through it, -when the lungs will immediately col- 
lapse again. Thus it is easily proved that if some force 

be applied to send air into the 
lungs, the elastic tissue in the air 
cells will stretch like rubber ; and 
that as soon as the force is removed, 
the elastic tissue will return to its 
former condition. 

The Pleura. — The pleura is a 
double membrane, covering the 
inside of the thoracic cavity and 
the lungs. One membrane is 
closely fastened to the inner walls 
Fig. 38.— (l) The end of a f the chest, while the other covers 

small bronchial tube; (2) air ,-, r i? ,i i r™ 

n the surtace ol the lungs. lhe 

space between these membranes 
is called the pleural cavity. The pleura secretes a fluid, 
so that its two surfaces may move against each other 
easily and without friction, as they do in ordinary 
breathing. An inflammation of this membrane is called 
pleurisy ; it is extremely painful, because each time a 
breath is taken, the lungs expand, causing the inflamed 
membrane covering the lungs to move against another 
inflamed membrane which forms the lining of the walls 
of the chest. 

Why Air enters the Lungs. — The mechanism of respi- 
ration is not unlike that of a pair of bellows. When the 




RESPIRATION 



101 



handles are raised, the inside of the bellows is made larger, 
and the air rushes in to fill the extra spaee. 

The chest is a tight box, with only one opening, and 
that at the top, — the larynx. If this box be suddenly 
enlarged, the air will rush in through the opening ; this 
is called inspiration. When the box ceases to enlarge, no 
more air enters. Im- 
mediately all the parts 
tend to return to their 
former condition, the 
box is made smaller, 
and the air rushes out 
of the opening at the 
top ; this is called ex- 
piration. From this 
we conclude that air 
enters the lungs be- 
cause the chest is made 
larger ; and that it 
leaves the lungs be- 
cause of the elastic FlQ 39> _ The position of the lungs, and 
nature of the lung their relation to certain organs : (1) the tra- 

substance. Before con- f ea = ( ^ the J cla 7 icle * ; (V^rfta; <*) * e 

lungs; (o) a dark curved line, showing the 
sideling how the chest position of the heart; (6) the diaphragm, ex- 
box is enlarged it will tending in a curved direction from oue side 
, ,-, . n . . n to the other; (7) the liver; (8) the stomach; 

be well to fix m the (9) the sterrmm 
mind the shape of the 

thoracic cavity, its contents, and the relation of certain 
organs to each other. A reference to Fig. 39 will show 
these relations. The lungs rise slightly above the collar 
bone (2) to form the apex of the chest : below, they 
rest upon the curved diaphragm (6), which divides 
the thoracic from the abdominal cavity. The relative 




102 



THE ESSENTIALS OF HEALTH 



position of the heart is shown by the curved line (5). 
Pressing up against the under surface of the diaphragm, 
on the right side, is the liver (7), while on the left 
side is the stomach (8). By glancing at this figure, 
it is easily understood that if the lower ribs be brought 
tightly together from any cause, as by tight lacing, the 
stomach and liver will be forced up against the diaphragm. 
As a result of this, it would be extremely difficult for the 
diaphragm to move downward, or, as illustrated in the 
figure, for the line 6 to become shorter. The application 
of this fact will be seen later. 

Inspiration. — When air is breathed in, the chest is 
enlarged in two ways. First, by the raising of the ribs 





Fig. 40. — Diagrams illustrating how the thoracic cavity is enlarged, as 
during inspiration. A, spinal column ; B , ribs ; C, sternum ; D, diaphragm ; 
E, lungs. The diagram to the right illustrates the thoracic cavity during 
expiration ; the one to the left, during inspiration. 

(which also enlarges the chest from side to side, because 
the ribs are curved), and second, by the contracting of 
the diaphragm. Attention has already been called to 
this thin muscle. When it relaxes, it is in the form of a 
vaulted partition, with its rounded portion rising into the 
cavity of the chest ; Fig. 40, right diagram, at D. When 



RESPIRATION 103 

the diaphragm contracts, it shortens, assuming more 
nearly a straight line; thus the convexity becomes greatly 
diminished. The contraction of the diaphragm, therefore, 
makes it descend toward the abdomen ; this must enlarge 
the thoracic cavity from above downward. Thus we con- 
clude that in ordinary, quiet breathing we do not draw 
the air into the lungs : the air rushes in, without aid, to 
fill the chest, which is made larger by the elevation of the 
ribs and by the contraction, or lowering, of the diaphragm. 

Expiration. — Ordinarily expiration, the breathing out 
of air, occurs without muscular effort. By the relaxa- 
tion of the muscles of the chest, the ribs fall back to 
their natural places. The relaxation of the diaphragm 
aided by the pressure of the abdominal organs from 
beneath pushing up against it, causes it to move up 
again into the chest. The distended elastic tissue of the 
air cells now seeks to return to its natural condition, thus 
diminishing the size of the air cells, and consequently the 
size of the whole lungs ; the thoracic walls keep in con- 
tact with the lungs as they diminish in size, and the air 
rushes out of the larynx. 

Sounds of the Chest. — When the air rushes in and out 
of the lungs, peculiar sounds are produced. These are 
easily changed by unhealthy conditions of the lung 
tissue ; the air may not enter a portion of the lungs ; 
it may enter a cavity ; or it may pass over a membrane 
either too dry or too moist. Any such departures from 
a healthy condition cause a change in the normal sounds. 
A careful study of these sounds enables the physician to 
determine the condition of the lungs. 

The Inspired Air. — Each inspiration brings about 
twenty cubic inches, or two thirds of a pint, of air into 
the lungs. It is, however, carried down only a short 



104 THE ESSENTIALS OF HEALTH 

distance, probably not much below the larger bronchial 
tubes. If the air should remain there, it would be of 
little use, but it does not. It reaches the smallest bron- 
chial tubes and the most tiny air cells, through what is 
called the " diffusion of gases," working under a very 
interesting law. The inspired air brings oxygen to the 
red corpuscles of the blood. See Plate II. 

The Expired Air. — If the expired air be collected and 
examined, it will be found to differ from the inspired 
air in the following particulars : (1) It has lost oxygen. 
The expired air contains nearly five per cent less oxygen 
than the atmospheric air. (2) It has gained carbon di- 
oxide. The expired air contains nearly a hundred times 
more carbon dioxide than the atmospheric air. This gas 
represents one of the waste products of the body, and must 
be removed. (3) It has absorbed water. The expired 
air is saturated with watery vapor. This is easily shown 
by breathing on a mirror, or on any polished surface. 
(4) It contains organic matter. The amount is usually 
very slight, and not easily detected. If it be in excess, 
it imparts a perceptible odor to the breath, which nray 
be offensive and unheathful. Even with the ordinary 
amount, its presence is easily detected if a number 
of persons be confined in a small room where there is 
poor ventilation. Under such circumstances the odor 
becomes very offensive, remaining in the room for hours 
after it is vacated by the people. (5) The expired air is 
usually warmer. To be more exact, it is generally about 
the temperature of the body, being unaffected by the 
variable temperature of the inspired air. 

Effects of Alcoholic Drinks on the Organs of Respiration. 
— Persons who are in the habit of using alcoholic bev- 
erages seem to be especially liable to colds and to bron- 



BESPIBATION 105 

chial affections. There is an inflamed condition of the 
throat and the larynx, and a slight but constant conges- 
tion of the lungs; that is, too much blood is in the lung 
tissue. Attacks of bronchitis are not infrequent. The 
chances of recovery from pneumonia are much less than 
with those who do not use alcoholic drinks. The liability 
to consumption is increased, because the weakened vital- 
ity is less able to resist the germs that cause this " great 
white plague," as it is sometimes called. 

The following quotations embody the experience of 
some eminent men : — 

u The drinker's incapacity to resist inflammation of the 
lungs is well known and dangerous." — Dr. A. Frick, 
Professor in the University of Zurich. 

"Nothing is likely to have such a decided influence in 
the prevention of tuberculosis as the general adoption of 
the practice of total abstinence from alcohol." — Dr. F. 
C. Coley, in the Lancet. 

The Lancet (London) of August, 1901, contains a re- 
port by Dr. F. X. Kelynack, which says: " According to 
F. Oliver, alcohol is particularly destructive to young 
people who are disposed to tuberculosis. According to 
Dickenson, tuberculosis is three times as frequent among 
drinkers as among abstinent people." 

In Dr. Hector McKenzie's " Text-book of Medicine," 
there is the following statement, "It is almost invariable 
to find tubercles present in the lungs of patients dying in 
the course of alcoholic paralysis." 

Effect of Tobacco on Respiration. — One of the most 
characteristic effects of tobacco is that breathing is less 
frequent and less deep, and the body, consequently, gets 
less oxygen, hence the blood is less pure and less energy 
is generated. 



106 THE ESSENTIALS OF HEALTH 

The Voice. — Four factors enter into the construction of 
the voice : (1) the breath, which is the power ; (2) the 
larynx, which makes the tone ; (3) the pharynx, mouth, 
and nose, which modify the tone; and (4) the organs of 
articulation. 

When the breath from the lungs comes against the deli- 
cate vocal cords it causes them to vibrate, thus producing 
sound. The force with which the air leaves the lungs has 
largely to do with the loudness of the tone. The pitch of 
the tone, whether high or low, depends upon the thickness, 
length, and tension of the vocal cords. This is precisely 
the case with the guitar, the piano, or any other stringed 
instrument. The quality of the voice is determined 
largely by the shape of the larynx and the upper air 
passages. 

The nervous and muscular mechanism of the larynx 
are indeed most marvelous. In response to the slightest 
nerve action, the muscles will tighten or relax the vocal 
cords with the most delicate nicety. 

There is a very close relation existing between the senses 
of hearing and of speech. The vocal organs cannot be 
brought to their highest development unless the ear be in 
perfect order. In the case of the persons whom we call 
" deaf and dumb " there is usually no defect whatever of 
the vocal organs, but never having been able to hear any 
sounds, not even those which they unintentionally pro- 
duced, such people are unable, without special teaching, 
to control the pitch of the voice. This is but another 
illustration of the necessity of caring well for the hearing. 

Speech or language may be said to consist of short 
sounds made by the vocal cords, called vowels ; and also 
of other sounds produced by the parts about the mouth, 
as the lips, tongue, palate, called consonants. The dis- 



RESPIRATION 107 

tinctness of speech depends largely upon the accuracy 
with which these consonants are formed. The peculiar 
and undesirable nasal tone which we often hear may be 
due to an unnatural condition of the parts, or to some 
trouble which might possibly be corrected by proper 
treatment. Sometimes the lower surface of the end of 
the tongue is attached too closely to the tissues beneath. 
Such persons cannot protrude the end of the tongue from 
the mouth; we say they are " tongue-tied." 

We must not underrate the value of a pleasant speech 
and voice. In the beginning we learn to speak from imi- 
tation ; hence, if a child hears harsh and coarse voices at 
home, he will unconsciously tend to develop the same kind 
of a voice. The child who hears only distinct and refined 
speech is receiving the best of vocal teaching. Those 
who have not had such advantages, or have been heedless 
of them, can usually by care and by attention correct the 
faults into which they have grown. In some cases this 
is quite impossible, owing to enlarged tonsils, adenoid 
growths, an improperly formed mouth, or other causes. 
But every effort should be made to discover such defects 
and to have them corrected, for the value to the individual 
of a refined and melodious voice will be more and more 
apparent as the years go by. 

One of the best methods of cultivating a pleasing speak- 
ing voice is singing. You may not have any especial gift 
along this line, and may never be able to do anything more 
than to sing in a chorus. Yet the training which comes 
from such study does a great deal toward cultivating cor- 
rect, distinct enunciation, and a pleasant speaking voice. 
Children should always be encouraged to sing. Singing 
is a valuable form of lung exercise ; it tends to develop 
the chest and acts as a preventive of lung diseases. 



CHAPTER XII 
VENTILATION 

Amount of Air Inhaled. — In the preceding chapter, it 
was stated that about twenty cubic inches of air are 
inhaled at each inspiration. Based on this statement, 
and making due allowances for the breathing being in- 
creased in frequency by muscular exertion, it is safe to 
say each person uses at least three hundred and fifty 
cubic feet of air, daily, in respiration. 

Oxygen supports Life. — A certain amount of oxygen 
in the air is necessary to support all life ; a much 
greater amount being required to support life in human 
beings than in some of the lower animals. In the case 
of man, if the amount of oxygen in the air be reduced 
one half, breathing continues with great difficulty. 

It requires more oxygen for the burning of a candle 
than it does to support life for the same length of time. 
Advantage is often taken of this fact to test the safety 
of entering a well, a vault, or an underground passage. 
A lighted candle is lowered into the cavity ; if a suffi- 
cient amount of oxygen be present, the candle will con- 
tinue to burn ; if not, it will be immediately extinguished. 
If the candle continues to burn, it will be safe for the man 
to enter the inclosure, for the reason that more than 
enough oxygen is present to support human life. 

Carbon Dioxide is a Poison. — Each respiration not only 
takes oxygen from the air, but it also gives to it small 
quantities of carbon dioxide and of some other harmful 

108 



VENTILATION 109 

ingredients. Hence it is injurious to breathe the same 
air even for the second time. If the air be poor iii 
oxygen, it will contain a large amount of carbon dioxide. 
As this gas is heavier than the air, it will fall when 
ron lined in a small space and left undisturbed. The 
air which is the least capable of supporting life is then 
found at the lowest level. For this reason, the air at 
the bottom of the well is not so pure as the air nearer 
the top. 

An animal placed in a closed space will absorb from the 
air a certain amount of the oxygen, and will give off 
carbon dioxide. In time the inclosed atmosphere will 
be so saturated with carbon dioxide that no more of it 
will pass from the body ; therefore the carbon dioxide 
is retained in the blood of the animal, causing speedy 
death. This carbon dioxide poisoning may occur while 
there is yet enough oxygen remaining in the air to sup- 
port life. 

From what has been said, we conclude that oxygen is 
necessary to life, and that an insufficient amount of it in 
the air will cause death. We conclude also that if the 
carbon dioxide be not removed, it may accumulate in the 
air, or in the body, sufficiently to cause death. The air 
we breathe, therefore, should have a certain amount of 
oxygen, and should not have an excess of carbon dioxide. 

There are many ways by which a person is warned when 
his system needs more oxygen and has too much car- 
bon dioxide. Headaches, restlessness, and drowsiness 
result from a deficiency of oxygen and a surplus of carbon 
dioxide. Unless the system is freely supplied with the 
former and can readily throw off the latter, the vital 
forces become lowered and the whole body predisposed 
to disease. 



110 THE ESSENTIALS OF HEALTH 

An Abundance of Air Necessary. — The above facts are 
given especially that we may appreciate the necessity for 
an abundance of fresh air. It does not follow that a 
person must live either out of doors or in a very large 
room ; but it does follow that, under all circumstances, 
an abundant supply of fresh air should be continuously 
furnished to the body. 

Pure Air. — The fact that the air is cold, and feels fresh 
to the face, is not proof that it is pure ; currents of air 
may be loaded with poisons. Pure air contains the proper 
proportion of oxygen, and is free from poisonous gases 
and disease germs. Out-door air is not necessarily pure, 
as some sewer gas or decaying animal matter may be near. 
Yet, as a rule, out-door air is the purest. 

It is not always possible to tell when the air is pure ; 
the best ordinary test we have is the sense of smell. 
Upon entering a room, if the air seems " close," it is suffi- 
cient proof that better ventilation is needed. After re- 
maining in a close room, one becomes accustomed to 
the odor and the closeness is not noticed, so the question 
of ventilation should be attended to as soon as the room 
is entered. 

A Deficiency of Air Dangerous. — Many cases are on rec- 
ord where persons have been poisoned by repeatedly 
breathing the same air. In the holds or cabins of ships, 
and in the deep cells of prisons, some terrible results have 
occurred from this cause. 

Many writers have referred to the " black hole of Cal- 
cutta " as an illustration of this fact. In a small room 
with only two narrow windows, there were confined one 
hundred and forty-six prisoners ; these persons were 
obliged to breathe the same air over and over again, for 
the windows were altogether too small to allow a sufficient 



VENTILATION 111 

amount of fresh air to enter. In eight hours one hundred 
and twenty-three of the prisoners were dead, while those 
whose lives were spared endured great suffering. 

Many rooms built to accommodate large numbers at a 
time, have an insufficient supply of fresh air, as, for in- 
stance, schoolrooms, lecture halls, and churches. While 
such a deficiency may not be enough to cause death, yet 
the effect on the body is marked and harmful. Drowsi- 
ness, with a dull, heavy headache, often results from a 
stay in such a poorly ventilated room. The listless and 
sleepy appearance of many a scholar is simply the result 
of impure air, not of a dull mind. " Break open the 
window ! " shouted a noted divine, in the midst of his 
discourse, as he saw many in his congregation asleep. He 
knew that the most brilliant speaker could not overcome 
the drowsy effects of impure air. 

If it becomes necessary to spend a considerable time each 
day in a poorly ventilated or overcrowded room, the whole 
body suffers. Living in poorly ventilated rooms enfeebles 
the whole body ; the appetite fails, the red corpuscles are 
reduced in number, the skin becomes colorless, and the 
entire system shows that it is suffering from too little oxy- 
gen and from too much carbon dioxide. Colds and coughs 
are frequent ; and the system has only slight power to 
resist disease of any kind. The whole condition is one of 
oxygen starvation and carbon dioxide poisoning. 

The Proper Amount of Air. — The supply of fresh air 
required for a room depends largely on the number of 
persons in the room ; for it is evident that a hundred per- 
sons will require a hundred times as much air as one 
person. 

Then, too, the presence of fires in the room must be con- 
sidered. The burning gas consumes much oxygen and 



112 THE ESSENTIALS OF HEALTH 

gives off carbon dioxide. For this reason a crowded hall, 
on a cold winter's evening, with heavy fires and lighted 
gas, requires much more ventilation than when a small 
company is assembled on a warm summer's da3 r . As it 
would cause discomfort to raise the windows and open the 
doors during the winter time, it follows that some system 
of ventilation is absolutely necessary for all places where 
persons are likely to assemble. 

Heating and Ventilation. — How to obtain an unfailing 
supply of fresh, outdoor air in our rooms is the constant 
study of those who plan homes and public buildings. 
Years ago this subject received no attention whatever. 
This was partly due to the fact that the method of heating 
the houses was far different from that used at the present 
day. The open fireplaces made a constant change of air, 
while the cracks about the doors and windows furnished 
avenues through which the fresh air entered the rooms. 

A furnace gives good ventilation, because as the warmed 
outside air enters the room from the registers, some of the 
air already in the room will find its way out through 
the ventilators or through the cracks ; thus a constant 
current of air is established. Great care should be exer- 
cised to see that the cold-air flue of the furnace receives 
its supply from out doors, not from in doors. If the out- 
door air entering the flue passes over decaying animal or 
vegetable matter, or an imperfect sewer, then the impure 
air may be conveyed- into the building, producing severe 
and perhaps fatal sickness. 

If the rooms be heated by a furnace, the air should be 
moistened by having it pass over a dish of water. Failure 
to do this results in the necessity of breathing very dry 
air, which is decidedly injurious. The open grates of 
modern days are good ventilators. An ordinary stove is 



VENTILATION 113 

a means of ventilation, for as the draught passes through 
it and up the chimney, fresh air comes in through the 
opening of doors and the crevices of the windows to take 
its place. 

Ventilation of the Sleeping Rooms. — Attention should 
always be given to the ventilation of the sleeping rooms. 
One third of our entire lives is spent in these rooms, yet 
how often do we neglect to make them either cheerful or 
healthful. If the builders of the house have not provided 
some method of ventilation, the air may be changed by 
raising the lower sash of one window and lowering the 
upper sash of another. If there is but one window in 
the room, it should be lowered from the top. A better 
method, however, is to admit the air into the room through 
wire gauze, used as window screens. There are a number 
of ventilators for sale in the market which allow a free 
passage of air and yet effectually prevent draughts. 

If the lower window sash be raised about six inches 
and a board be placed under it, completely filling the 
space between it and the window casing, some ventilation 
will be established between the sashes. This is a fairly 
good method for the winter, but hardly sufficient for the 
more quiet air of summer. 

Some persons seriously object to opening the windows 
of their sleeping rooms at night, for fear of " the deadly 
night air." Yet all the lower animals breathe it, from 
the delicate and tender young to the strong and the aged. 
Soldiers and hunters breathe it as they sleep beneath their 
tents and in the open air, while many invalids have been 
restored to health by living out of doors both day and 
night. 

The bed should be well aired each day. Immediately 
after dressing, throw the upper clothing of the bed over 



114 THE ESSENTIALS OF HEALTH 

a chair, raise high the windows in the room and allow the 
clothing to become well aired for an hour or two at least 
before it is placed on the bed again. Indeed, a very good 
rule to remember is this : Clothing worn during the day 
should be aired at night, and clothing used at night 
should be aired in the daytime, preferably in the sunlight. 

Ventilation of the Schoolroom. — The teacher generally 
gives personal attention to the ventilation of the school- 
room, and the proper authorities should see to it that some 
method is devised by which the change of air may be 
constant and abundant. This does not mean ventilation 
at noon and recess only ; it means that the change should 
be continuous and uninterrupted, for anything short of 
this fails to answer the purpose. 

After the hearty plays of recess, when the skin is 
moist with perspiration, the pupils should not sit down 
in a cool room. This is too often the cause of colds and 
coughs. The schoolroom should be of an even tempera- 
ture all through the day ; therefore there must be a con- 
stant and uninterrupted change in the air. Ventilation 
is improper if it produces a current of air ; for if a 
draught of air be allowed to strike the back of the neck, 
or any sensitive part of the body, it is very likely to cause 
a cold. These currents of air should be carefully avoided, 
especially when the body is resting after active exercise. 

Ventilation of the Cellar. — The cellars of houses and 
other buildings are often great reservoirs of foul air. 
The cellars of dwellings frequently have stored in them 
quantities of vegetable matter which give off injurious 
gases as they decompose. As the cellar is usually dark, 
the decaying organic matter is unseen, and hence it 
remains until the escaping gases penetrate the rooms 
above, and endanger the health of the inhabitants. Cel- 



VENTILATION 115 

lars should be well ventilated, kept scrupulously clean, and 
so built, if possible, that the sunlight can enter them. 

Deodorizers. — One odor may cover another without 
destroying it. A free use of cologne may cover the odor 
of a poorly ventilated room, but it will neither remove the 
carbon dioxide and the organic matter, nor bring more 




Well-arranged Vegetable Bins 

oxygen. Coffee and sugar are often burned in a room 
to destroy some disagreeable odor. They do not destroy, 
however; they simply cover one odor with another more 
powerful. Any substance that will replace or cover the 
odor of another, and yet not destroy it, is called a 
deodorizer. 

Disinfectants. — There are substances which actually 
destroy odors; these are true disinfectants. They are 



116 THE ESSENTIALS OF HEALTH 

used to purify sewers, cesspools, and sinks, and to de- 
stroy the germs of scarlet fever, diphtheria, and smallpox. 
A disinfectant may be perfectly odorless itself, and yet 
have the power of destroying the most offensive odors. 
The chlorides and sulphates of the metallic salts are 
powerful disinfectants. Preparations of the chlorides are 
on the market which are reliable and convenient. The 
sulphate of iron (copperas) dissolved in Water in the 
proportion of four ounces to the gallon, is a useful disin- 
fectant for cleansing gutters, drains, sewers, etc. 

Sunlight. — We cannot place too high a value on sun- 
light; the strong rays of the sun are sufficient in them- 
selves to destroy many forms of germ life. There is 
great cleansing power in sunlight, and we should let it 
pour into our sleeping room for hours at a time if possible. 
Do not be afraid of the sunlight in the other rooms of 
the house. At some time during the day, whenever the 
rooms are so situated as to make it possible, let the sun 
send in its health-giving power. The wise housekeeper 
will not hesitate to risk the fading of the carpets, appre- 
ciating how fortunate it is that such a life-giving power 
as sunlight can enter the home. 

Sweeping and Dusting. — It may seem as though any one 
could do properly such simple work as sweeping and 
dusting. We must recall, however, that dust is not 
simply dirt, but may contain many harmful disease germs. 
If these cannot be removed, they certainly ought not to 
be kept floating in the air. It is important therefore to 
sweep thoroughly, yet gently; to sweep the floor or carpet 
clean and yet raise but little dust. It is better, when the 
furniture will allow, to use a slightly dampened cloth for 
dusting ; the usual way of dusting often means simply the 
removal of the dust from one part of the room to another. 



VENTILATION 117 

Heavy draperies and curtains should be frequently taken 
out of the house and thoroughly shaken or dusted. 

Boys should remember that it is not the kind and manly 
thing to do to come into the liouse with dirty boots or 
shoes, or with the clothing all covered with snow. Clean 
the boots and shoes and brush the clothing before entering 
the living rooms. 

Back Yards. — People who keep their front yards in fine 
condition sometimes thoughtlessly neglect the back yard. 
It should be kept free from refuse material of every kind. 
Water should not be allowed to stand in tubs or barrels, 
and thereby become the breeding place of mosquitoes. 
Pools of water should not be allowed to exist there any 
more than in the front yard. Another reason why the 
back yard should be kept tidy and free from all decaying 
material is because the windows from some of the sleeping 
rooms of the house usually open directly toward this yard. 

Contagious Diseases. — The air we breathe may seem to 
us to be very pure because it is free from any odor, and 
yet it may contain the germs of very contagious diseases. 
By contagious diseases, we mean a disease that can be 
carried from one person to another. The germs of such 
diseases as diphtheria and scarlet fever are easily carried 
by means of the clothing, or even in the dust of the atmos- 
phere. A person does not necessarily have the disease 
to which he has been exposed ; but it is always best to be 
very careful. The one who is ill with any contagious dis- 
ease should be kept in a well-ventilated room, and no mem- 
bers of the family admitted except the mother or nurse. 

Boards of Health. — If every person knew the impor- 
tance of regarding the laws of health and would carefully 
follow them, no police regulations would be required; 
but this is not the case. Hence nearly every state, nearly 



118 THE ESSENTIALS OF HEALTH 

every city, and nearly every village has its Health Com- 
missioner or Board of Health. Over two hundred years 
ago the famous Izaak Walton said, " That which is every- 
body's business is nobody's business"; this is true even 
to-day. Therefore, it becomes necessary that one person, 
the Health Officer, or a few persons combined, the Board 
of Health, should watch over the health of the community, 
and look out for those things which, since they affect the 
community as a whole, might otherwise be left by each 
person for the next person's attention and care. These 
health officials are expected, for instance, to see that the 
school buildings are well ventilated, that the drinking 
water supplied for the pupils is pure, and that proper 
protection is given if there are any contagious diseases 
among the children. They also watch the supplies of 
foods in the markets, in order that decayed or overripe 
fruits and vegetables and tainted meats may be destroyed, 
Boards of Health should also regulate the removal of 
garbage and waste, should see that houses are provided 
with proper drainage, and should, in a word, have the 
health of the whole community at heart. 



CHAPTER XIII 



THE KIDNEYS 




General Description. — The kidneys are two in number, 
one on each side of the spinal column. The lower edge 
of each comes just above the waist line. Each kidney is 
about four inches in length, 
two inches in breadth, an 
inch in thickness, and about 
rive ounces in weight. 

A kidney resembles a bean 
in shape. The rounded 
edge of each kidney is 
placed toward the side of 
the body, while the hollowed 
edge is next the spinal 
column. The kidneys are 
completely covered with a 
thin membrane, called the 
capsule. Each kidney is 
supplied with blood by an 
artery which arises from the 
aorta. This artery enters 
the kidney as shown at A, 
Fig 41. After the arterial 
blood has circulated through the kidney, it is returned 
through a vein at V. This vein empties into the large 
vein which lies by the side of the aorta. 

119 





Fig. 41. — A kidney : A, an artery ; 
V, a vein ; D, the duct that carries 
away the materials filtered from the 
blood. 



120 



THE ESSENTIALS OF HEALTH 



Minute Structure. — The most interesting portion of the 
kidney is found in that part near the rounded outer edge, 
to the left of Fig. 42. Here active changes are constantly 
taking place. In this portion there are seen, with the 
microscope, vast numbers of small, round, red bodies, 
which are but the beginnings of long, narrow tubes. 

Each body consists of coils of cap- 
illary blood vessels, surrounded 
by a membrane. While the blood 
is circulating through the kid- 
neys, certain substances are taken 
from the blood. These substances 
are carried away through the 
minute canals of the kidney (the 
fine, fan-shaped lines) until they 
empty into a large duct, shown 
at (7) and (8), Fig. 42. This 
Fig. 42. — a section through duct carries the secretion directly 
akidney: (1,2,3,4), collections tQ a reservoils designed espe- 
cially for its reception, called the 
bladder. 

Secretions of the Kidneys. — 
When the blood reaches the kid- 
neys it contains one substance in 
particular which must be removed 
most serious results would follow, 
it is held in solution by 




of tubes, or canals; (5), papillae 
on which the tubes open; (6), 
below the end of the dotted line 
is a blood vessel ; others are 
seen above this; (7), the dilated 
beginning of the duct (8), which 
carries the secretions from the 
kidney. 



from the body or 

This substance is called urea: 

the water that composes such a large part of the blood. 

Urea contains nitrogen which was supplied to the body 

as a part of the nitrogenous foods ; at this stage, however, 

it is no longer of any worth or use to the body, for it is a 

waste product. The muscles contain nitrogen, and as 

they work they wear out; the nitrogen which is in the 



THE KIDNEYS 121 

urea represents a certain amount of worn-out muscular 
tissues. Urea also comes from other worn-out tissues 
that contain nitrogen, such as the various glands of the 
body. It is therefore an excretion, something which 
must be removed from the body, hence the kidneys are 
called excretory organs. A great part of the nitrogen 
which we take into the body with our food is at last re- 
moved from the body by the kidneys in the form of this 
urea. 

The water secreted by the kidneys holds many other 
substances in solution besides urea. If the kidneys from 
any cause should completely fail to perform their work, 
life could exist for only a few hours , Should they but 
partially perform their work, then the other organs of 
excretion would be called upon to do extra work, For 
a time they might do so, but soon they would suffer from 
the overwork and serious results would follow. 

The work of the three great excretory organs — the 
lungs, the skin, and the kidneys — is so carefully adjusted 
that each has its own particular duties, yet all work in 
perfect harmony. 

Danger from Use of Alcoholic Drinks. — The use of 
alcoholic drinks is considered by some physicians to be a 
serious cause of various forms of kidney trouble. It may 
be a direct cause, through its irritating effects, or an indi- 
rect one by causing the liver to become diseased and unable 
to perform its functions. In the latter case, the poisons 
that the liver should take from the blood pass on to be 
thrown out by the kidneys. The result may be either the 
overworking of the kidneys or the irritation of them from 
an abnormal amount of poison, or both. 



CHAPTER XIV 
THE BONES 

General Description. — There are two hundred and four 
distinct bones in the body. This does not include the 
teeth, the knee pan, and a few other bony structures. 
When the bones are for the purpose of protecting delicate 
parts they are generally broad and flat — as the bones of 
the skull and shoulder blade. When strength and light- 
ness are both desired, as in the large bones of the arms 
and legs, the bones are then round and hollow. 

The Periosteum. —A thin membrane, called the perios- 
teum, surrounds each bone. It is composed of two layers, 
an outer layer of firm tissue, which is simply for support 
and protection, and an inner layer of cells. This inner 
layer is essential to the life of the bone, and its cells are 
even capable of forming new bone. 

The periosteum is well supplied with blood vessels, some 
of which pass directly into the bone through minute open- 
ings on the surface. These openings can be seen on any 
bone from which the periosteum has been removed. 

Compact and Cancellous Tissue. — If one of the long 
bones of anj r animal be sawed lengthwise, it will be found 
to be hollow, except at the ends. The hard, thick wall, 
midway between the ends of the bone, is called the 
compact tissue ; while the spongy, honeycombed bone, 
occupying the center of the ends of the bone, is called 
the cancellous tissue. See Fig. 43. The smaller bones 

122 



THE BONES 



123 



and the flat bones are not hollow ; they have an outer 
layer of compact bone, within which is the spongy bone, 
or cancellous tissue. 

The Marrow, — The large central cavity of the long 
bones, and all the spaces in the 
spongy bone, are filled with a 
yellowish or reddish substance, 
called marrow. It consists 
principally of fat cells and 
marrow cells. These marrow 
cells doubtless give rise to large 
numbers of the red corpuscles 
of the blood. 

Animal and Mineral Matter. 
— The blood vessels, bone cells, 
marrow, nerves, and the frame- 
work of fibers, constitute the 
animal matter of bone. This 
makes the bone soft and yield- 
ing. But the body must have 
a stronger protection and sup- 
port than this. We find, there- 
fore, that some mineral sub- 
stance is added to the animal 
matter, making the whole tissue 
of the bone firm and hard. 

By remembering that fire 
will destroy animal matter and 
that acids will dissolve mineral 
matter, some interesting results 
may be obtained. For instance, 

if the fresh bone of a chicken or cancellous bone shows atthe ends; 

while the compact, hollow bone 

of any animal be placed in the forms the shaft. 




Fig. 43. — Longitudinal section 
of the femur. The spongy or 



124 THE ESSENTIALS OF HEALTH 

fire, and subjected to heat for a considerable time, all the 
animal matter can be burned out. The shape of the bone 
will not be changed ; it will only become lighter and 
whiter. After such treatment it can be easily broken and 
pounded into a fine powder. 

The mineral matter consists largely of lime. This can 
be removed by soaking the bone in a weak acid for a 







Fig. 44. — Cross section of bone, not so highly magnified as Fig. 46. Canals 
(a) for blood vessels are seen cut crosswise. The spider-shaped cavities for 
the bone cells are also seen. 



few hours. The shape of the bone will not be changed ; 
it will only lose its hardness, and may be easily bent in 
any direction. All the blood vessels and the bone cells 
still remain in the bone (Figs. 44, 45, 46). 

From these experiments we easily draw the conclusion 
that, if the bones do not contain the proper amount of 
mineral matter, they will bend, and will be unable to keep 
their shape and properly support the tissues around them. 
If there is a deficiency in the amount of animal matter, 



THE BONES 



125 




the bones will be too brittle, and liable to break if any 
extra strain be brought upon them. 

Nature very wisely provides that in early life there 
should be an excess of the animal matter in bone. If 
this were not so, the tumbles and falls which are the com- 
mon lot of all chil- 
dren at play would 
result in many seri- 
ous injuries. But 
the bones of youth 
have such a spring 
to them that chil- 
dren are not likely 
to fracture them. In 
old age the bones 
are very brittle, and 
are much more easily 
broken. 

Broken Bones. — When a bone is broken, the surgeon 
places the broken ends together, and holds them in 
position by means of splints and bandages. Nature imme- 
diately begins the work of mending the bone. First, a 
liquid substance surrounds the broken ends. This grad- 
ually becomes firmer and harder, and in a few weeks 
develops into true bony structure. Thus the ends become 
so firmly united that the bone is as strong as ever. 

Changes in Bone. — =The bones are not fully developed 
until one is at least twenty-five years of age. And it 
should be remembered that even after this, they, in some 
degree, change their soft substance. When the bones 
have an abundance of animal matter, as in early life, they 
can be molded, and their natural form greatly changed. 
This is well illustrated by the Chinese custom of binding 



Fig. 45. - 



Longitudinal section of bone ; showing 
the bone canals, magnified. 



126 



THE ESSENTIALS OF HEALTH 



the feet of their young girls until an unsightly deformity 
is produced which often results, later in life, in pain and 
disease in these parts. 

Young children or infants should not be placed contin- 
ually in one position, and when very young, they should 

not be allowed to remain too 
long in the sitting posture. 
If they are made to sit or to 
stand too early, the bones may 
be bent or changed so as to 
interfere with their proper 
development. In caring for 
children, we must constantly 
remember how tender and 
easily bent are the growing 
bones which form the solid 
structures of the young bodies. 
Otherwise the child may be- 
. come bow-legged, or may sus- 

Fig. 46.— Longitudinal section of °° . J 

bone, highly magnified. A blood tain some other, but perhaps 

vessel is seen at the top, another at less evident, change from the 
the bottom. In living bone, the -, i o ,i *, 

spider-shaped cavities here shown normal slla P e of the bon J 

are filled with bone cells. Thus we structure, 

learn that bone is a living tissue. ^ Good Figure. A fine 

erect figure generally gives evidence of a healthy body 
and of a mind that is alert and well poised. Young 
children who are strong and w r ell usually stand erect 
and are graceful in their motions. Too often they 
lose this erect figure as they grow older, and form bad 
habits in sitting and in standing, when at wwk and 
play. Then the balance and symmetry of the figure 
must be restored by a series of exercises that shall 
develop the muscles which have been weakened by con- 




THE BONES 



127 



stant bad position. When 
the student is absorbed in 
studying, it frequently 
happens that the body is 
allowed to droop more 
and more until finally it 
is in a crouching position. 
In this way the chest is 
narrowed, the circulation 
hindered, and the student 
cannot breathe properly. 
A correct reading posi- 
tion at a desk is shown 
below. Among the bad 
positions frequently taken 
by careless students, one 
of the most common is 





A Correct and Comfortable Positi 
for Beading and Study. 



An Unnatural Position, Cramping the 
Lungs and Digestive Organs and interfering 
with the Freedom of the Circulation. 



shown by the illustration 
above. In this case, too, 
the harm is intensified by 
the fact that the desk and 
seat are too low for the 
student. The study chair 
and table used at home, as 
well as the desk and seat 
used in the schoolroom, 
should be made to fit the 
body properly, even if some 
pains has to be taken to 
secure the right adjust- 
ment. 

It is not in studying 
alone that one frequently 



128 



THE ESSENTIALS OF HEALTH 



takes a bad position. Many people have a habit of resting in 
attitudes that are even worse for the body. Some of these 
positions are so injurious and so commonly taken that it 
seems desirable to show here for comparison a comfortable 
and restful sitting position and some of the incorrect 
positions that are frequently assumed. The lines under 





This Position shows a Comfortable 
and Restful Way of Sitting, with 
Muscles relaxed. The Spine is prop- 
erly SUPPORTED AND THE BODY IS WELL 
POISED. 



This Position relaxes the Shoul- 
der Muscles, tending to cause Round 
Shoulders, and it also stretches the 
Lower Part of the Body in a very 
Undesirable Way. 



the illustrations call attention to some of the injuries 
resulting from those wrong positions in sitting which are 
shown. Ask some one who has made a study of physical 
training to explain more fully why these positions are 
harmful. We should avoid many such faults if we real- 
ized that it is not well to rest one part of the body by 
throwing unnatural work on the other parts. Notice how 
this applies to the incorrect positions as here illustrated, 



THE BONES 



129 



and how comfortably the body is poised for resting in 
the correct sitting position, as shown on page 128. 

In standing, it is better to rest the weight on both feet. 
The habit of resting the weight on one and the same foot 
is sure to make the hip bones grow out of shape ; it will 
also bend the spine, and make it incline toward one side. 





This Position will cause Round 
Shoulders ; all the Muscles in the 
Upper Part of the Body are stretched 
Forward, with the Shoulders curving 
the Wrong Way. 



This Position throws the Hips out 
of Balance and will in Time cause the 
Eight Hip, which is thrown out by the 
Eaising of the Foot, to become notice- 
ably Larger than the other Hip. 



In walking, the whole body should be erect, with the chin 
held in and the chest held high. If the body does not 
take this position naturally and easily, it is because we 
have allowed ourselves to become careless and to form 
bad habits, which we must correct. 



CHAPTER XV 
THE SKELETON 

Object of the Skeleton. — All the higher animals are 
provided with a bony support, or framework, for the 
organs and tissues of the body. This framework is called 
the skeleton. It serves also as a protection from injury. 
In some of the lower animals, the skeleton is entirely on 
the outside. The oyster is completely inclosed in its hard 
shell, and is thus well protected against the attacks of 
enemies. The lobster has an exterior skeleton also, but 
the parts are so arranged that there is considerable free- 
dom of motion. The turtle has not only an interior 
skeleton, but also a large plate, or exterior skeleton, of 
hard material. This animal can withdraw its head beneath 
the outer skeleton, and thus the whole body is protected 
from violence. 

The animals which have exterior skeletons do not have 
such freedom of motion as is required by the higher 
animals. Therefore, in man, beasts, birds, fishes, and 
some other animals, the skeleton is entirely within the 
body. The ribs, spinal column, and breast bone make a 
nearly complete covering for the heart and lungs. 

The Bones of the Skull. — The head is composed of 
twenty-two bones. Eight of these make a solid, strong 
covering for the brain, while fourteen compose the bones 
of the face. At the base of the brain is a large opening 
through which the spinal cord and a number of large blood 
vessels pass. (Study Plate V for location of bones.) 

130 




PLATE V 

The names and locations of the principal bones of the body : (1) frontal ; 
(2) parietal ; (3) occipital ; (4) temporal ; (5) superior maxillary ; (6) inferior 
maxillary ; (7) nasal ; (8) clavicle ; (9) sternum ; (10) humerus ; (11) ulnar ; 
(12) radius. Notice that the radius has crossed the ulnar. When the hand 
is turned so that the thumb is outward (not inward as here represented), and 
the palm of the hand is to the front, then the radius is all on the outward 
side, and lies parallel to the ulnar. (13) Small bones of the haod ; (14) bones 
of the ringers ; (15) pelvic bones ; (16) femur ; (17) tibia ; (18) fibula ; (19) small 
bones of the foot; (20) bones of the toes. 



132 



THE ESSENTIALS OF HEALTH 



The frontal bones, one on each side, form the forehead. Two 
bones, the parietal, one on each side, form the top or crown of the 
skull. The bone at the back and lower part of the skull is the 
occipital bone; and the opening through this bone allows the spinal 
cord to pass to the brain. There is one bone on each side of the skull 
called the temporal bone. Directly back of 
each ear is a portion of this bone called the 
mastoid. This is of especial interest because 
in certain diseases of the ear it becomes seri- 
ously affected. 

The superior maxillary bones, the upper 
jaw bones, are the large bones which form 
the whole of the upper jaw. They also 
form the bony roof of the mouth and the 
bony framework for the upper part of the 
cheeks ; the upper teeth are inserted in these 
bones. The inferior maxillary or lower jaw 
bone is the largest and strongest bone in the 
face ; in it the lower teeth are located. The 
nasal bones are two in number and are placed 
at the upper part of the nose, forming the 
" bridge " of the nose. The lower part of the 
nose consists of cartilages and soft tissue. 

The Spinal Column. — The spinal 
column consists of twenty-four small 
bones, — resembling those illustrated 
at Figs. 49 and 50, — and two irregu- 
lar bones at the lower end of the 
column. 

A reference to Fig. 47 shows that 
the spinal column is not straight, 
but forms a series of curves. These 
curves give additional elasticity to the column. 

Each bone in the spinal column is called a vertebra, from 
a Latin word signifying " to turn," as a joint. Thus a 
translation or definition of the word would be, "a joint of 



Fig. 47. — The spinal 
column. The right side 
of the figure is toward 
the back of the body. 



THE SKELETON 



133 



the spinal column." Each ver- 
tebra has within it a large open- 
ing, through which passes the 
spinal cord. The vertebras are 
held together by ligaments, and 
are so placed, one directly over 
the other, that the central open- 
ings forni a continuous canal ex- 
tending the entire length of the 
spinal column. This is called 
the spinal canal; it furnishes a 
firm protection to the spinal 
cord. Between the vertebrae, 
as shown in Fig. 48, are disks, 
or cushions of elastic cartilage. 
This cartilage resembles rubber 
in its elasticity. Its great use 





Fig. 49. — The upper surface of one 
of the vertebrae of the neck: A, open- 
ing in each side for a blood vessel; 
B, point on which the bone above it 
rests ; C is the long process that extends 
from the back of the spinal column ; 
SC, opening in the center for the spinal 
cord. 



Fig. 48. — Two vertebra?, A, A, 
slightly separated to show the 
cushion of cartilage, B; the posi- 
tion of the spinal cord is indicated 
atC. 

can be appreciated when 
it is stated that the com- 
bined thickness of all 
these cushions is over six 
inches. They greatly di- 
minish the shock and jar 
that come to the body from 
jumping and running. 

Nearly all the vertebrae 
resemble those shown in 
Figs. 49 and 50. Fig. 49 
illustrates a vertebra of 
the neck, as viewed from 
above. The long process, 
C, is the one that is so 
easily felt at the back of 
the neck. The darkly 



134 



THE ESSENTIALS OF HEALTH 




shaded oval portion at the top of the figure, immediately in 
front of the opening for the spinal cord, is the place of 
attachment of the elastic cartilage. Fig. 50 represents a 

vertebra lower down the spinal 
column, and viewed from the side. 
At A is represented the front of 
the vertebra, and the place where 
the cartilage is attached. The long 
process, B, extends backward and 
^^J downward, forming a part of the 
Fig. 50. — One of the verte- ridge, which may be felt extend- 

brse viewed from the side: A, • down the center of the back> 
represents the body of the ver- 7L 

tebra; b, the process. The " atlas is so named be- 

cause it supports the globe of the 
head. It* stands at the top of the spinal column, and dif- 
fers in shape from the other vertebrae. Upon this bone, 
which remains stationary, 
the skull rests, nodding, or 
moving backward and for- 
ward, at will. 

The "axis," or second 
vertebra of the spinal col- 
umn, is so named because it 
forms the pivot upon which Fig. 51. — The atlas, or the first 
the head turns from side to vertebra, viewed from above: (1) the 

process of the axis ; (2) the places on 




which the skull rests ; (3) the opening 



side. This pivot is the 

Strong bony projection, re- for the spinal cord. The dotted line 

sembling a tooth, which rises re P resen * a ^^ which holds the 

o process (1) m place. 

perpendicularly from the 

upper and front part of the axis. When the atlas and 
the axis are in position, they correspond to Fig. 53. 
During the sidewise movement of the head, the skull and 
the atlas move together, the atlas swinging around the 



THE SKELETON 



135 




pivot of the axis. A study of .Figs. 51, 52, and 53 will 
aid in making this clear. 

The Ribs. — There are twelve ribs on each side of the 
body. The ribs are so curved 
that each makes an elastic arch 
of bone. Behind, the ribs are 
attached to the spinal column. 
In front, the first seven are at- 
tached to the breast bone by 
means of cartilages. The next 
three are fastened to each other 
by cartilages ; while the last two 
have, no attachment in front, 
hence they are called the float- 
ing ribs. 

The Thoracic Cavity. — The fig. 52.— The atlas (A) and 
thoracic cavity, so called because the axis ^ viewed from the 

side: (1) the process on which 

it contains the thorax, or chest, the atlas fcurns (seen also at h 

is inclosed by the Spinal Column Figs. 51 and 53); (2) the place 
i i • j i -i 1 ,on which the atlas rests. 

behind, the sternum, or breast 

bone, in front, the ribs on the sides, and the diaphragm 
below. The spaces between the ribs are filled in with 
1 muscular tissue, so that 

surrounding the thoracic 
cavity there is a complete 
wall, formed partly of 
bone and partly of muscle. 
All that part of Fig. 39 
which is above the dia- 
phragm, (6), represents 
Fig. 53. — The atlas and axis in position, the thorax. In this cav- 
front view: (1) the toothlike process of . 4-1 l u 

the axis, showing above the atlas ; (2) the lt Y are tlie lun g s > heart, 

axis; (3) the atlas. and large blood vessels. 




136 



THE ESSENTIALS OF HEALTH 



The Upper Extremities. — There are five large bones and 
several small ones that belong to the arms, the upper ex- 
tremities of the body. The clavicle, or collar bone,, 
extends from the front of the shoulder to the top of the 
sternum ; it keeps the shoulders from stooping. The scap- 
ula, or shoulder blade, forms the back of the shoulder, 
between the shoulder joint (Fig. 54) and the spine. At its 
upper and outer part is a cavity, or socket, for the recep- 
tion of the head of the humerus, or upper arm bone, which 
extends from the shoulder to the elbow. The two bones 




Fig. 54. — A, Front view of the right B, Back view of the same joint, 
shoulder joint, without collar bone. 

(1) Scapula; (2) bony prominence on scapula; (3) humerus; (4) point of 
attachment of collar bone. The ball (head) of humerus is held tightly to the 
socket of the scapula by means of the ligaments here shown. 

of the forearm, or lower arm, are the radius and the ulna. 
The radius and ulna are placed side by side, and so arranged 
that the radius can move partly around the ulna, giving 
the hand the power of rotation, or turning. The radius 
is on the side of the arm corresponding with the thumb. 
The remaining bones of the arm form the hand. 

The Pelvis. — The pelvis is a kind of bony basin inclosed, 
on the back, by the two lower bones of the spinal column ; 



THE SKELETON 



137 



on the sides, by the large hip bones (Fig. 55); and in front, 
by the pubic bones. The curved shape of the upper edge 





Fig. 55. — A, hip joint with outer liga- 
ments removed ; B, hip joint with ligaments 
in place. 



of the hip bones gives a strong support for the abdominal 
organs. The sides furnish a means of attachment for the 
legs, while the back gives attachment to the spinal column. 
The Lower Extremities. — The femur, or thigh bone 
(Fig. 56), extends from the thigh to the knee ; it is the 




Fig. 56.— The femur. 



longest, largest, and strongest bone in the body. The 
tibia and fibula, placed side by side, form the lower part 
of the leg. The tibia forms the ridge in the front of 



138 



THE ESSENTIALS OF HEALTH 



the leg, while the fibula forms the outside of the leg. The 
patella, or knee pan, protects the knee in front. 

Bones of the Foot. — The bones of the foot are so united 
that they form an arch (Fig. 57), of which only the ends 
touch the ground. This arch is useful in protecting the 
body from severe shocks, as in the act of running or jump- 
ing ; for it is evident that when the weight of the body is 




Fig. 57. — Side view of the bones of the foot, naturally arranged 
in the form of an arch. 



thrown upon the arch, its center is pressed downward, thus 
acting as a spring. 

The Joints. — Whenever bones form a joint, or meeting 
place, they are covered with a layer of highly polished 
cartilage (Fig. 58). This gives some slight elasticity, and 
also reduces the friction. Covering the cartilage is a very 
thin membrane which is constantly secreting, or pouring 
out, a watery fluid, called the synovial fluid, or joint water. 
It serves the same purpose as does oil on the wheels and 
joints of machinery. 

The Ligaments. — The bones are held together at the 
joints by bands of tissue, called ligaments. These are 
very dense and strong, and capable of withstanding great 



THE &KELETOM 



139 



strain without injury. Fig. 55, B, illustrates how the 
head of the femur is buried in the socket prepared for it ; 
Fig. 55, A, illustrates the hip joint after the outer liga- 
ments have been removed, and the bone pulled partly out 
of its socket. A strong ligament still 
remains, holding the head of the femur 
to the center of the socket. 

Sometimes the ligaments are unduly 
stretched, or slightly torn, as when the 
wrist or ankle is sprained. Such an 
injury usually causes great pain, and 
recovery is slow. The ligaments may 
be so broken or torn that the bones 
slip out of their proper places. The 
bone is then said to be " out of joint," 
or dislocated. Sometimes in healthy 
persons the ligaments are very loose, 
so that, by the action of the muscles 
alone, some of the joints can be dislo- 
cated at will. Such persons are said 
to have loose joints. 

Varieties of Joints. — Joints may be 
either movable, imperfect, or immov- 
able. The movable joints, such as the 
shoulder and elbow joints, vary ex- 



Fig. 58. — A longitudi- 
nal section through a 
joint, showing a layer 
of cartilage over the end 

ceedingly in their power of motion, of each bone: (i) the 
The imperfect joints are such as are °^v e ayers ° 
found in the spinal column. There 
is some slight motion between the vertebrae, due to the 
elasticity of the thick plates of cartilage. It is the same 
motion that can be made after cementing a thick plate of 
rubber between two blocks of wood. The elasticity of the 
rubber would allow a certain freedom of motion and yet 



140 THE ESSENTIALS OF HEALTH 

the parts would not move upon one another. Examples 
of the immovable joints are seen in the union of the bones 
of the skull. The edges of the bones are so fitted into 
each other that they form an unyielding joint, or suture. 
Because of the delicacy of the brain it is important that 
the covering should be firm and unmovable. 

The Ball-and-socket Joint. — When the head of one bone, 
which is more or less round like a ball, fits in the socket, 
or depression, of . another bone, the joint is called a ball- 
and-socket joint. The bone with the round head can 
move in any direction, the extent of its motion depending 
only upon the shape of the socket. If the socket be deep 
and small, as in the hip, the motion will be limited, but if 
the socket be shallow and broad, as in the shoulder, then 
the motion will be free in every direction. 



Fig. 59. — A section through the elbow joint : H, the humerus; U, the ulna; 
R, the radius; P } the process, which prevents the arm from moving back of a 
certain line. 

Hinge Joints. — When two bones are joined together so 
that they can move back and forth in only one direction, 
like the hinges of a door, the joint is called a hinge joint. 
The elbow is the best example of a hinge joint (Fig. 59). 
The movement is limited, for while the arm can be bent 
forward and straightened, it cannot be bent backward. 
The knee is another example of this joint. 

Pivot Joints. — The rotary motions of the head, by 
which the skull and the atlas turn upon the pivot of the 
axis, furnish an illustration of a pivot joint. 



CHAPTER XVI 



THE MUSCLES 



General Description. — The great bulk of the body, out- 
side of the skeleton, is composed of muscles. The muscles 
give the general outline to the 
body and make nearly one half ggg 
its total weight. Nearly all the 
muscles are arranged in pairs, so 
that the two sides of the body are 
almost alike. Some of the mus- 
cles are very minute, while others 
are long enough to reach from 
the hip to the knee. In the 
majority of animals, they are of 
a deep red color, forming the lean 
meat or flesh. In many of the 
fishes and in some of the birds, 
the muscles are white, or of a 
light yellow color. 

The Uses of Muscle. — The 
muscles are primarily the organs 

* __ ,- rri -i Fig. 60. — Voluntary muscle, 

oi motion. lney also act as a . +1 .. ,, , , n , . K : 

J with its blood vessels: (1) the 

protection to the blood vessels muscle fibers; (2) the blood ves- 

and the nerves ; they inclose the sels ' ma £ nified - 
large thoracic and abdominal cavities ; they serve as 
cushions to diminish the force of falls and blows; they 
fill up irregularities in the skeleton, and thus add to the 
symmetry of the whole body. 

141 




142 



THE ESSENTIALS OF HEALTH 



Two Kinds of Muscle. — The muscles are, in respect to 
their duties, divided into two classes, the voluntary and 
the involuntary. The voluntary muscles are so called be- 
cause their movements are under the control of the will. 
Such muscles can be used whenever we wish or will 
to use them, as the muscles of the face or the arm. 
Others cannot be controlled in this 
way ; they do their work independent 
of any action of the will, hence they 
are called involuntary. The muscles 
of the stomach and the heart are of 
this variety. The heart beats, the 
stomach contracts, and we are power- 
less to stop their action. 

As a rule, all those movements in 
the body most essential to life are not 
under the control of the will. Yet 
many of the involuntary muscles can 
be controlled for a short time. An 
illustration of this is found in ordi- 
nary breathing. We breathe a cer- 
tain number of times a minute and are 
entirely unconscious of it ; still, by an effort of the will, 
we can breathe faster, slower, or deeper. Even the volun- 
tary muscles can be made to contract involuntarily by a 
sharp blow, or by some fright. While voluntary muscles, 
therefore, are controlled by the will, they are not invari- 
ably so controlled. Nearly all the voluntary muscles are 
attached to bone at each end ; while the involuntary are 
not attached to the skeleton, but are found in the walls 
of hollow organs, as the stomach and the intestines, and 
in the walls of the arteries. 
Structure of Voluntary Muscle. 




Fig. 61. — A muscular 
fiber, magnified. 



If a piece of lean meat, 



THE MUSCLES 



143 



which is voluntary muscle, be boiled, it will appear as if 
ready to fall apart into little bundles of tissue. These 
bundles may be easily divided into still smaller ones, by 
separating them carefully with needles. In this way 
minute threads of tissue are obtained. If one of these 
be examined with a microscope, it will be found to consist 
of many smaller threads, called muscular fibers. In Fig. 
60, four of these fibers are seen side by side, with their 
accompanying 
blood vessels. In 
this figure, and 
also in Fig. 61, 
fine lines may be 
noticed running 
directly across 
each fiber. Be- 
cause of these 
markings, this va- 
riety of muscle 
has been called 
striated muscle. 
Notice the blood 
supply, as shown in Fig. 62. On examining any piece of 
lean meat, the bundles are seen as strings of red flesh, 
with white connective tissue between them. Boiling the 
meat dissolves this connective tissue to a certain extent, 
so that the bundles of fibers more readily fall apart. 

Structure of Involuntary Muscle. — Involuntary muscle 
is quite simple in its structure. It consists of a number 
of spindle-shaped cells, held together by a cement. This 
cement substance is found throughout the body. It is 
of the nature of glue, or cement, and it firmly holds many 
of the cells of the body together. Fig. 63 represents 




Fig. 62. — The capillary blood vessels of muscle, 
magnified. The drawing is made from the same 
specimen as Fig. 60, only the muscular fibers are not 
shown. 



144 



THE ESSENTIALS OF HEALTH 




some involuntary muscle which has been treated with 
dilute acid. The acid has dissolved the cement, and the 

cells are seen well separated 
from each other. These cells 
are very minute, and a high 
power of the microscope is 
required to see them. 

The Tendons. — The volun- 
tary muscles are sometimes 
attached directly to the skin 
and to other soft tissues ; but 
the great majority are con- 
nected to the bones by firm, 
white cords. These white, 

FiG.6£-The cells ofi involuntary shining cordg are caUed ten . 

muscle, magnified. ° 

dons. The tendons have no 
power of themselves to contract. They simply serve the 
purpose of cords, connecting the working part of the 
muscle with the part which it has to move. The parts 
acted upon may be situated a considerable distance from 
the controlling muscle ; thus, the ends of the fingers are 
moved by the muscles of the forearm. 

The tendons serve another purpose : owing to their 
compact nature they occupy much less room than do 
the muscles, thus the small size of the wrist and ankle is 
made possible. Were it not for this fact, these joints 
would be covered with thick muscle, and it would be quite 
impossible to have the necessary freedom of motion. The 
tendons at the wrist can be easily felt, while the one 
attached to the thumb is easily seen on the back of 
the hand. The largest tendon in the body, shown in 
Fig. 57, is called the Undo Achillis. According to the 
Greek legend it was at this point that Achilles received 



THE MUSCLES 145 

his death wound, as there was no other portion of his 
body that could be wounded. 

Figf. 64 illustrates the muscles of the forearm and their 
tendons. The tendons are held tightly down at the wrist 
by firm bands of tissue. Some of the 
tendons extend to the very ends of the 
fingers, so that when the muscles of 
the forearm contract, they move the 
most distant parts of the hand. The 
tendons are inclosed in sheaths, through 
which they easily glide. 

Muscular Contraction. — By placing 
the fingers of one hand upon the fleshy 
part of the other hand, at the base (or 
ball) of the thumb, the tissue will feel 
soft and comparatively thin. This tis- 
sue consists of voluntary muscle, and 
can be made to contract by an effort of 
the will. With the fingers still in the 
position indicated, place the thumb on 
the end of the little finger ; the muscle 

now feels thick and hard. From this 

Fig. 64. — The mus- 

we Conclude that when a muscle COn- c les of the arm, ending 

tracts, it becomes thicker and harder. in the white tendons at 

We know that a muscle shortens when 

it contracts, because it moves the parts to which it is 

attached. 

A study of Figs. 66, 67, 68, 69 will illustrate the 
principle upon which all voluntary muscles act. If 
the muscles on the front of the arm should shorten, 
the hand would be raised ; while if the opposing mus- 
cles on the back of the arm should shorten, the hand 
would be drawn down again. If the muscles on the 



146 



THE ESSENTIALS OF HEALTH 



front of the leg should shorten, the toes would be raised ; 
while the opposing muscles would raise the heel. Thus we 




Fig. 65. — A, a muscle relaxed, before it contracts; B, the same muscle con- 
tracted ; it is shorter and thicker. 

learn that when a muscle contracts, it becomes thicker, 
harder, and shorter ; and that all the movements of the 
body are caused by such contractions (Fig. 65). 

In the case of the 
involuntary muscles, 
the individual spindle- 
-shaped cells contract. 
1 If the cells be arranged 
in a circular manner, 
as around the arteries, 
then their contraction 
will diminish the size 
of the vessel. For 
the same reason, if the 

muscular cells that 
Fig. 66. — Diagram illus- „ - 

trating the action of the mus- ±orm tlie Walls Ot the 

clesof thearm. A,themuscle, stomach contract, they 

or flexor, which raises the ^j dimini h the gize 
forearm. Fig. 67. — B, the 

muscle, or extensor, used to of the cavity, and will 

straighten the arm. f orce out j ts contents. 




THE MUSCLES 



147 



But a muscle cannot remain in a state of contrac- 
tion for any great length of time. It soon tires and is 
obliged to relax. After a short rest, however, it is again 
ready for work. All muscles must have rest, or they 
will soon wear out. 

The Use of Levers in the Body. — Have you ever 
watched workmen moving heavy stones or timbers for a 
new building? You 
might often see them 
take a pole, put one 
end on the ground 
under the timber to be 
moved, lift up on the 
pole, and let the timber 
slide along. Some- 
times, instead of lift- 
ing up on the pole 
placed under the tim- 
ber, they would put a 
small block below the 
pole, close to where it 
goes under the timber, 

-. ., . . , , . Fig. 68. — Showing the muscles of the lower 

and then raise the tun- leg contracted at A t0 raise the body on the 

ber by pressing down toes. Fig. 69. — The contraction of the op- 
on the pole. These posing muscles to lower the heel. 

are two forms of what we call "prying." An engineer 
would use somewhat different terms. He would tell you 
that the pole was a lever, the ground or the block on 
which the pole rested was the fulcrum, and the object to 
be moved was the weight. We apply the same principle 
whenever we move our bodies ; without some form of 
"prying" we could not sit or stand or walk or lift. 

Try a few experiments in prying. Take a book and 





148 THE ESSENTIALS OF HEALTH 

pry it along the desk with a ruler, or lift it with the ruler 
by placing a pencil under the ruler near the book. Then 
lay the ruler on the floor, place a foot on one end and a 
book on the other ; grasp the ruler near the book and lift 
up. The book is raised as readily as before. Then slip 
the fingers along the ruler close to the foot and lift. You 
will have to lift hard to raise the book in this position ; 
this last experiment illustrates what you do unconsciously 
every time you lift your hand. If you place a book on 
the palm of your hand and raise it slowly, the book is the 
weight, the forearm is the lever (corresponding to the 
ruler), your elbow is the fulcrum, serving as your foot 
did in the other experiment, and the big muscle on the 
front of the arm is the power applied to raise the weight. 
Owing to the short space between the elbow (the ful- 
crum), and the power (the muscle), and to the long space 
between the power (the muscle) and the weight on the 
hand, the muscle has to exert a large amount of force to 
move the weight. In other movements of the body we 
use different forms of this lever principle, and it would be 
interesting to trace them out. From the hint that has 
been given you will appreciate why muscles cannot con- 
tinue violent exercise without some rest. 

Harmony in Muscular Action. — The muscles which bend, 
or flex, the joints are called the flexors ; while those 
which bring the bent parts back again are called the 
extensors. Examples of the former are those muscles on 
the front of the arm which raise the hand ; while examples 
of the latter are those on the back of the arm which pull 
the hand down again. 

From this description, it is evident that opposing mus- 
cles must not act at the same time ; for if the flexors and 
extensors should equally contract, and pull upon the parts 



THE MUSCLES L49 

to which they are attached, there would be no motion what- 
ever. To give free motion to a part, the opposing muscles 
must be finely adjusted to each other. In cases of spasms, 
or convulsions, the muscles do not act in harmony, and 
the body becomes stiff and rigid. 

The delicacy of the adjustment of muscular action is 
well illustrated in the muscles of the face. Often the 
expressions of the face tell more than do uttered words. 
An unconscious contraction of a muscle, be it ever so 
slight, may betray, to the close observer, pain or pleas- 
ure. A slight contraction of a muscle lifts the brow, and 
a smile covers the face ; while a change in another mus- 
cle is followed with an expression of suffering and pain. 
The infinite variety of tones that can be produced by the 
human voice is due to the position and tension of the 
vocal cords, and these are controlled by muscular action. 

The Control of the Muscles. — All the muscles are under 
the control of the nervous system. The nerves serve as a 
connecting medium between the brain and the spinal cord, 
and the distant muscles.. The nerve force is sent from 
the brain, or spinal cord, down, the. nerve fibers to. the 
distant muscles stimulating them to contract. If this 
connection be broken, there will be no muscular action. 
Training the muscles therefore means training the nerves 
and the brain as well. When w T e learn to use the muscles 
of the hands skillfully, as we must to do good carpentry 
or good metal work, we have accomplished two different 
things, — the muscles have been taught to act with deli- 
cacy and precision, and the nervous system (brain, spinal 
cord, and nerves) has been taught to give its orders to 
the muscles that are involved more accurately and more 
specifically than it could do without this training. Hence 
the advantage of the different forms of manual training 



150 



THE ESSENTIALS OF HEALTH 



that are introduced into school work. These are impor- 
tant not only to the pupil who expects to earn his living 
by some form of skilled labor, but also to the pupil who 




expects later to take up some profession, and may there- 
fore never have another opportunity to get the mental 
discipline that comes from rightly directed manual labor. 

Effects of Alcohol on Muscular Work. — Professor Cushney, 
University of Michigan, says : " Over and over it has been 
demonstrated beyond question that regiments supplied with 
alcoholic liquors are less capable of long marches and suffer 
more from fatigue than others to which no alcohol is issued." 

Dr. E. Destree, late professor in the University of Brussels, 
said : " Nothing whatever in physiological chemistry authorizes 
us to admit that alcohol has a favorable influence on muscular 
work. Bunge asserts that the effects felt are only a symptom 
of brain paralysis, a benumbing of all feeling of weariness." 

Dr. Graham Lusk, Professor of Physiology in University 



THE MUSCLES 151 

and Bellevue Hospital Medical College, writes: "It seems 
hardly necessary to refer to the fact that the use of alcohol 
in armies, as a means of obtaining additional expenditure of 
physical force, has long since been abandoned. After taking- 
alcohol, the sum total of work done will not be increased, but 
rather diminished. The depressant effect is the predominat- 
ing factor in the long run." 

Sir Victor Horsley, M.D., a celebrated brain specialist of 
England, states :" The disadvantageous effect of alcohol on per- 
sons performing muscular work is well known, and it has been 
proved from the records of military expeditions that the best 
physical results are obtained under total abstinence from alcohol. 
The evidence is overwhelming that alcohol in small amounts 
has a most deleterious effect on voluntary muscular work." 

The Most Important Muscles. — Nearly all the muscles have very 
difficult names of Latin origin, which refer to their location or to the 
work they have to do. To illustrate : The occipito-frontalis muscle is 
the one that extends from the occipital bone to the frontal bone. 
When this muscle contracts, it raises the eyebrows and draws the 
scalp forward. It gives to the face the expression of surprise ; and 
when the contraction is more marked, the expression of fright or 
horror. 

An illustration of a muscle named by the nature of its work is the 
masseter muscle, the name being derived from a Latin word, meaning 
" chewing." Hence the muscles on each side of the face are called 
the " chewing muscles." By placing the fingers over the angle of the 
lower jaw, just over the lower molar teeth, and pressing the teeth 
firmly together as in chewdng, the muscle will be felt to thicken and 
harden as it contracts. 

Other important muscles are as follows : The buccinator muscle is 
between the upper and lower jaws at the sides of the face. During 
mastication these muscles contract holding the cheeks firm so that the 
food is kept between the teeth. When the cheeks are distended with 
air, the buccinators contract and dispel it from between the lips. This 
name is given to the muscle because it is used so largely in blowing 
glass and in blowing wind instruments. It is named from the Latin 
word meaning " trumpet." 



152 THE ESSENTIALS OF HEALTH 

The tongue is a large voluntary muscle capable of a variety of 
movements. 

The broad flat muscle that covers all of the upper and back part of 
the neck and shoulders is called the trapezius. 

On the upper and front part of the chest is a large muscle, the 
pectoralis major, or large muscle of the chest. It aids in drawing the 
arm inward and forward, and is often very largely developed in strong 
men. 

The diaphragm is a thin muscle that completely divides the thoracic 
from the abdominal cavity. It is attached to the ribs and to the 
spine. By its contraction it takes a very prominent part in respira- 
tion. The intercostal muscles are between the ribs. By contracting 
they raise the ribs and thereby increase the capacity of the chest. 
They are very important to respiration, aiding in the work of the 
diaphragm. 

The large thick muscle which completely covers the shoulder is the 
deltoid. The biceps covers the whole of the front of the upper arm. 
It is the great flexor muscle of the forearm. It is this muscle that is 
largely used in climbing or in drawing the body up when hanging by 
the hands to a limb or pole. Its swelling and hardening may be 
easily felt by placing the left hand over the front of the right arm 
and then raising the right forearm forcibly, as if lifting a heavy 
weight. This muscle is largely developed in athletes, and in all who 
are engaged in heavy manual labor. 

The triceps is the great extensor of the arm, covering its entire back 
surface ; it is the direct antagonist of the biceps. There could be no 
bending of the forearm if both these muscles should act at the same 
time. 

The muscles of the thigh are very large and strong, many of them 
extend from the hip to the knee. The greater part of the calf of the 
leg is formed by a strong, large muscle called the gastrocnemius. It 
terminates below in a tendon called the tendo Achilles. This muscle, 
with smaller ones by its side, is constantly brought into use in walk- 
ing, standing, leaping, etc. It draws the heel up and thus raises the 
whole body from the ground; while the body is thus supported the 
other leg is carried forw r ard. 




PLATE VI 



The location and action of some of the more important muscles : (1) the 
biceps, contracted, bending the arm; (2) flexor muscles of the forearm, con- 
tracted, pulling the tendons of the wrist, thereby bending the fingers ; (3) pec- 
toralis major, the chest muscle, draws the arm across the front of the chest; 

(4) the deltoid, covers the shoulder, carries the arm outward and upward; 

(5) the triceps, contracted, extending the arm ; (6) extensor muscles of the 
forearm, contracted, pulling on the tendons, (7) (8), extending the thumb and 
first finger; (9) muscles about the hips; (10) flexor muscles of the thigh, con- 
tracted, bending the leg ; (11) gastrocnemius muscle, contracted, pulling on the 
tendo Achillis (12), and slightly raising the heel. The whole weight of the 
body is on the right leg, hence all of these large muscles are tense and firm. 



CHAPTER XVII 
EXERCISE 

Exercise Necessary. — Exercise of the muscles is abso- 
lutely necessary to keep them healthy and strong. 

But no one admires a man who has strong muscles, and 
a sluggish brain ; so we conclude that it is unwise to de- 
velop one particular part of the body and to neglect some 
other portion. The endeavor should be to develop all 
parts equally well. A proper amount of exercise is one of 
the essential conditions for perfect bodily development. 

Many a young and enthusiastic pupil has been so 
carried away with his desire to excel in his studies, that 
every hour spent in other labor, or in rest, was regarded 
as so much time wasted. He failed to remember that the 
sound mind must be in a sound body to bring forth its 
highest and best results. It is of vital importance that 
at least one or two hours of each day be spent in outdoor 
exercise. No matter how cold the air may be outside, no 
one need fear taking cold if the body be kept in active 
exercise, and if rest be taken in the warm house. Out- 
door exercise is always to be preferred to that taken 
indoors, because outdoor air is the purest. 

Work and Rest. — Each time a muscle contracts, there 
is a waste of some of its substance. Daring the active 
work of a muscle, the waste far exceeds the repair. The 
worn-out material accumulates faster than it can be car- 
ried away, and the body experiences a sense of fatigue. 

154 



EXERCISE 



1,V 



If exercise be continued until the body is greatly fatigued, 
and if such exercise be frequently repeated, the muscles 
will gradually waste away, just as they would if they were 
not used at all. 

If a muscle is made to work, it must have its periods 
of rest. The heart never appears to be tired. It beats 
on year after year, with an astonishing regularity. But 
it would soon wear out, did it not have a period of com- 
plete rest between its beats. In order that the muscles 




A Class taking Gymnastics Out of Doors. 

may be kept in a healthy condition, there should, be proper 
exercise followed by repose. 

The Amount of Exercise. — If exercise is so important 
for the general health, what is to be considered a proper 
amount ? This varies within wide limits, according to the 
health and habits of the individual. If the organs and 
tissues of the body are poorly nourished, so that even 
slight exercise gives great fatigue, then the exercise should 
be very short, and followed by long rest. But the fatigue 
following exercise felt by those in delicate health will 
grow less and less if the exercise be steadily continued ; 
always remembering to rest as soon as one begins to feel 



156 THE ESSENTIALS OF HEALTH 

tired. On the other hand, a healthy person may exercise 
until all the muscles are thoroughly tired, and yet, after 
a night of sound sleep, awake feeling all the better for 
the work. 

It is safe to say that general exercise should not be too 
violent ; overexercise is nearly as bad as no exercise. 
Any exercise is too violent which leaves the body ex- 
hausted. Such exercise unfits the body for regular work 
and may prove injurious to the nervous system. Health- 
ful exercise should bring a restful feeling, a desire for 
work, and refreshing sleep. 

Walking. — The gentlest form of active exercise is 
walking. It throws into action nearly all the larger 
muscles of the body, except those of the arms. The ad- 
vantage of this form of exercise over gymnastics is that 
it takes the person out of doors. Here the varied scenery 
has its exhilarating effect on the nervous system, and 
purer air is inhaled. To derive the full benefit of walk- 
ing, it should be undertaken with a feeling of freedom 
and pleasure. 

The Bicycle. — One advantage in using the bicycle is 
that -the mind is refreshed by the changing scenery and 
the whole body is brought into active service. It is a 
convenient and economical conveyance, and its proper 
use forms one of the most valuable exercises. But the 
rider should sit in a correct position, and not bend low 
down over the forward wheel. He should be careful 
also not to overexert himself climbing hills. 

Other Forms of Exercise. — Rowing is a very healthful 
exercise, and tends to develop many parts of the body. It 
is likely to prove injurious when long continued at a time, 
and when the muscles are used too violently. Horseback 
riding is an excellent exercise. It brings into play nearly 



EXERCISE 



157 



all the muscles, while the fresh air and changing scenery 
impart a healthy tone to the entire nervous system. 
Tennis, golf, baseball, football, sliding, skating, — all 
these are pleasant and beneficial forms of exercise. 

How to find plenty of exercise in the open air does not 
trouble the farmer's boy, who has to get up early in the 
morning, do his part of the chores, and then walk a long 




An Outdoor Gymnasium, — a City Substitute for Country Sports. 



way to school. But he is the boy who eats heartily, sleeps 
well, and is not easily fatigued. He is laying the sure 
foundation for a healthy body. 

Benefits of Exercise. — The muscles are not the only 
parts benefited by exercise ; the general health of the 
entire body is greatly promoted. Were this 'not true, but 
little would be said about muscular exercise ; for simply 
to become physically strong should not be our highest 



158 THE ESSENTIALS OF HEALTH 

ambition. The mind of man is more to be admired than 
his muscular strength. It is because a healthy body is 
such a great aid to a vigorous mind that an abundance 
of exercise is so persistently urged. 

A proper amount of exercise increases the healthy action 
of the heart, and makes the blood flow more freely through 




Outdoor Gymnastics in a Vacation School. 

the organs and tissues. It brings more air into the lungs, 
increases the appetite, and aids digestion. From this it 
logically follows that bodily exercise tends to give more 
activity to the mind and to strengthen the mental powers. 
Effects of Alcoholic Drinks on Muscular Action. — The 
value of muscular action depends upon the contracting 
power of the muscle, the exactness of its control by the 



exkiu isE 159 

brain, and upon its power of endurance, that is, the length 
of time the muscle can sustain a given amount of work. As 
the limit of endurance approaches, the feeling of fatigue 
comes on and increases until rest becomes necessary. 

The man who earns his living by muscular labor natu- 
rally wishes to have strength of muscle and to have it 
hold out until his task is accomplished. But if he takes 
a drink of beer or ale, or some other alcoholic liquor, 
when he begins to feel tired, he reduces his working 
ability for the rest of the day. He may think for a little 
while that he feels better, because the alcohol dulls his 
nerves and makes him less conscious of his weariness, but 
he quickly becomes more tired than he was before. 

He may think too that he can do more and better work 
while the effect of the alcohol lasts, but here again he is 
mistaken, as careful tests will show. The difference in the 
quantity and quality of his work can be clearly seen by 
careful comparison made by another person whose brain is 
unclouded by alcohol. The reason the drinker himself is 
deluded is because the alcohol that dulled his brain until 
he no longer felt tired, dulled his judgment also. At the 
same time, the poisoned brain could not so well control 
the movements of the muscles and a portion of the energy 
he expended was misdirected. This is a particularly seri- 
ous matter to the men engaged in industries that require 
exact and skillful work. 

Efficiency requires strict attention to the matter in hand, 
and the ability to hold in check an impulse to move until 
the mind decides just how the motion should be made in 
order to be right. One of the first effects of alcohol is to 
lessen the power of self-control and to increase the tendency 
to muscular movement ; hence in proportion to the amount 
he drinks it robs the skilled workman of his skill. For the 



160 THE ESSENTIALS OF HEALTH 

same reason, the man who drinks is out of place in any 
employment that involves responsibility for life and prop- 
erty. Railroad superintendents and other managers of 
large and important industries have learned from experi- 
ence what men of science have verified by laboratory 
experiments ; namely, that alcohol diminishes working 
ability. The individual, the business concern, or the nation 
that would strive for the front rank in the world's work 
must cut loose the shackles imposed by alcoholic drinks. 

At one time Mr. Carnegie added ten per cent to the wages of his 
abstaining workmen. When inquired of as to the reason for this 
action, he wrote : — 

" Men are not required to be total abstainers, but all who are can 
obtain from me a gift equal to ten per cent of their wages, with my 
best wishes, upon stating that they have abstained for a year. I 
consider total abstainers worth ten per cent more than others, espe- 
cially if coachmen, yachtsmen, or men in charge of machinery." 

Professor Adolf Fick, of the University of Wurzburg, said : " Every 
penny which the workman spends for alcoholic drinks is not only 
wasted but employed for a destructive purpose. The workman would 
use the money expended for alcohol to best advantage if he purchased 
fatty foods and sugar in its stead." 

Effects of Tobacco on Working Ability. — Dr. J. W. Seaver, Super- 
visor of Physical Training at Yale University, has made some interesting- 
studies of the effect of tobacco upon muscular exertion. He says : — 

" Whenever it is desired to secure the highest possible working 
ability of the organisms, as in athletic contests where the maximum 
effort is demanded, all motor depressant influences are removed as far 
as possible, tobacco being one of the first substances forbidden. . . . 
Experiments carried out by Dr. W. P. Lombard, of the University of 
Michigan, have shown that even moderate amounts of tobacco in the 
form of smoke lower the working power of the human, muscle by a 
high percentage. ... In from five to ten minutes after beginning to 
smoke an ordinary cigar, muscular power began to diminish, and in 
an hour, w 7 hen the cigar was burnt, it had fallen to about twenty-five 
per cent of its initial value. The total work of the time of depres- 
sion, compared with a similar normal period, was 24.2 to 44.8." 



CHAPTER XVIII 

THE SKIN 

General Description. — The skin forms a strong, close- 
fitting garment for the body, protecting the delicate and 
sensitive parts beneath. In the case of a medium-sized 
man the skin is equal to sixteen square feet of surface. It 
is not fastened tightly to 
the tissues ; but is held 
by delicate bands of con- 
nective tissue (Fig. .70), 
which are of a loose 
or open nature. This 
allows the skin to be 
raised and gathered in 
folds, and also permits 
free movements of the 

. . Fig. 70. — Cells from connective tissue, 

skm over the joints and magnified. 

muscles. In some parts 

of the body, as the soles of the feet and the palms of the 
hands, it acts as an elastic pad. It affords protection 
from external injuries of a mechanical nature, and also from 
the action of chemicals or poisonous substances. It binds 
all the outer parts of the body together, giving it sym- 
metry of outline. It has much to do with regulating the 
temperature of the body. 

The skin is also a great excretory organ, actively con- 
cerned in the removal from the body of substances that 
would prove injurious, if allowed to remain. 

161 




162 



THE ESSENTIALS OF HEALTH 




Adipose Tissue. — The connective tissue beneath the skin 
usually contains more or less adipose, or fatty tissue, Fig. 
71. In thin persons there may be very little fat, and the 
outlines of the tendons and muscles, and even the shape of 

the bones, may show through 
the skin. In fleshy persons the 
fat may be in great abundance, 
pushing out the skin, and 
causing the wrinkles and out- 
lines of the parts beneath to 
Fig. 71. -Fat cells, magnified; disappear. In the average 
to the right are five connective healthy body there is always 

tissue cells partly filled with fat. £ , • .-, , . -, ,-. 

some tat in the tissues beneath 
the skin. In old age the fat is likely to disappear, caus- 
ing the skin to form in folds or wrinkles. The fatty 
tissue is of use as an aid 



in retaining the heat of 
the body, thus taking 
the place of so much 
extra clothing. 

The Two Layers of 
the Skin. — The skin is 
composed of two layers, 
the epidermis and the 
dermis. The epidermis, 
which is also called the 




Fig. 72. — A cross section of the epi- 
dermis, magnified : (1) the layer of cells 
nearest the surface of the body; (2, 3, 4) 
other layers of cells. 



cuticle, or false skin, forms the outer layer. It is com- 
posed entirely of cells, Fig. 72. The outer ones are very 
hard and dry and are being constantly removed. The epi- 
dermis has neither blood vessels nor nerves ; it is, there- 
fore, bloodless and without feeling. For these reasons 
it is possible to remove nearly all the epidermis by gently 
scraping the skin with a knife without causing pain or the 



THE 8KIN 



163 



flow of blood. But as soon as the true skin, the dermis, is 
reached, the scraping causes pain and the- blood begins to 
flow. 

In a blister the epidermis is entirely separated from the 
dermis. An ordinary blister on the hand shows a thin 
membrane, raised from the parts beneath, and separated 




Fig. 73. — A section of the human skin, magnified: (1) the epidermis; 
(2) the duct of a sweat gland ; (3) a sweat gland : (4) the ending of a 
nerve, for the sense of touch ; (5) coils of minute blood vessels ; (6) a hair 
follicle, in which is a hair ; (7) a muscle, which can move the hair follicle. 

from them by a watery fluid. Such a membrane may be 
cut without giving pain or starting blood; for it is the 
epidermis of the skin. After the thin membrane is 
removed, if the red surface beneath it be touched, it will 
be found highly sensitive and is easily made to bleed. 



164 THE ESSENTIALS OF HEALTH 

Epidermis rapidly Changing. — The epidermis is a good 
illustration of the wear and waste of the body. The outer 
cells are constantly falling off in vast numbers; immense 
numbers are removed daily by the friction of the clothing, 
and by the work of the sponge and towel at the bath. 
This loss is being steadily made up by the formation of 
new cells in the deeper parts ; these come to the surface 
as the ones over them disappear. 

If all of the epidermis were removed at once, the parts 
left would be very red and tender ; but in the case of 
the blister, a few cells of the epidermis are left clinging 
to the true skin ; these rapidly multiply until within a 
few days a complete new epidermis is formed. After 
some fevers, as during the " peeling " of scarlet fever, 
large masses of cells are removed together. 

Uses of the Epidermis. — The outer layer of the epi- 
dermis, as seen at (1), Fig. 72, consists of closely packed, 
hard cells which make a very complete and almost impene- 
trable covering. Therefore, the epidermis is a protection 
against the absorption of poisons. 

The surgeon is not harmed while operating on diseased 
portions of the body, because the epidermis prevents the 
absorption of any poisonous matter; but there are many 
cases on record where the skin on the surgeon's hand was 
accidentally cut or broken while operating, thus allowing 
diseased matter to be absorbed, producing blood poison- 
ing and even death. Immersing the whole hand in pois- 
onous matter might possibly do no harm, provided the 
epidermis were in a perfect condition everywhere ; but 
a prick might cause death. The epidermis also protects 
the parts beneath from the sudden changes of heat and cold. 

The Coloring of the Skin. — The color of the skin de- 
pends largely upon the character of the deepest cells of 



rut: skix L65 

the epidermis, as at (4), Fig. 72. In very light skins, 
these cells are colorless ; in darker skins, the cells have 
a slight amount of dark coloring matter in them; while 
in the darkest skins, the coloring matter is very abundant. 
The destruction of these deep cells causes the epidermis 
to appear perfectly white, as it does in certain diseases. 
The white skin of the Albinos is due to the absence of 
any coloring matter in these cells. A free supply of 
blood to the skin gives it a red or pink color ; while any 
interference with the action of the liver may give a 
jaundiced or yellow color to the skin. 

The Tactile Bodies. — The tactile bodies give the sense 
of touch. They are situated in the dermis, or true skin ; 
they reach to the epidermis, but do not penetrate it. 
Wherever the sense of touch is the most delicate, there 
are found the largest number of tactile bodies. Over one 
hundred of these bodies have been counted in a space -^ 
of an inch square. They are very small, averaging no 
larger than -g4^ of an inch in length. Thus the micro- 
scope shows that while it is true that the epidermis has 
neither blood vessels nor nerves, yet just beneath it are 
nerves, illustrated at (4), Fig. 73, especially arranged for 
the sense of touch. The dermis is also well supplied with 
blood vessels. 

The Sweat Glands. — The sweat glands are found in 
the deep parts of the dermis, or in the tissue immedi- 
ately beneath the dermis. In Fig. 73 these glands are 
represented as minute tubes arranged in circular coils. 
That part of the tube which is not coiled, but which ex- 
tends from the gland to the surface of the skin, is called 
the duct : the duct pursues a spiral course, as represented 
in the figure, and opens on the surface with a funnel- 
shaped enlargement. 



166 THE ESSENTIALS OF HEALTH 

If the ridges which appear so plainly on the ends of 
the fingers and palms of the hands be examined with a 
small magnifying glass, it is possible to see the minute 
depressions in the center of them ; these represent the 
openings of the sweat glands. The view obtained will 
resemble that given in Fig. 74. The openings are quite 
close together, in some places averaging as many as three 
thousand to the square inch. From the surface of the 
skin to the coiled glands is about one fourth of an inch. 
It is estimated that there are over three millions of 
these glands in the entire skin. 

The Perspiration. — The perspiration is a colorless fluid 
secreted in the coils of the sweat glands. It is of very 
( ^_ r ___ w?w ^^ simple composition, over 99.5 

per cent of it being water. 
Some inorganic substances, as 
sodium chloride (common salt), 
give it a salty taste ; while 
some organic substances im- 
part to it an odor. The 
perspiration is a continuous 
secretion. When it is small 
in amount, the water is evap- 

-^L^^^> ' *_ & * orated from the skin at once, 

^~~i^^i^ therefore its presence on the 

^•- - ■ - : :^^^^ skin is not noticed; this is 

fig. 74.-The surface of the called the ^sensible perspira- 

skin, slightly magnified, showing tion. As soon as the secretion 
the openings of the sweat glands. is increased, it does not all 

evaporate, but gathers as drops of sweat on the surface ; 
this is called the sensible perspiration. Many conditions 
cause the amount of perspiration to vary. In some indi- 
viduals the whole amount per day is very small ; while in 




THE SKIN 167 

others it is very large. It is a fair average for the year 
through to say that about two pounds are secreted each day. 

There is a marked difference in the perspiration of 
the lower animals ; the horse perspires freely ; the ox to 
a slight extent only ; and the dog but little, if any. The 
panting of the dog after exercising allows much water to 
be given off from the tongue and from the body through 
the lungs; and in this way the object of regulating the 
temperature of the body is gained, as will be described later, 

Conditions affecting Perspiration. — An increase in the 
temperature of the surrounding air will cause an increased 
secretion of the perspiration. Individuals who work in 
furnaces, or in places of very high temperature, often 
perspire as much in an hour as the average person will in 
a day. Those who perspire freely ought to drink a large 
amount of water to supply the loss, or the system will 
soon become exhausted. An extra amount of water in 
the system will increase the secretion. Muscular activity 
is well known to do the same. Certain drugs excite very 
copious perspiration, while other drugs diminish it. The 
secretion is lessened by cold ; ill fact, it may be suddenly 
arrested by this means. Any departure from health also 
may cause it to vary, ranging from the hot dry skin of 
fever to the profuse night sweats of consumption. 

There is a direct relation existing between the action of 
the kidneys and the skin. In summer, when the skin is 
active, the secretion of the kidneys is much lessened ; 
while in winter, when the skin is less active, the work of 
the kidneys is increased. 

Object of the Perspiration. — The chief object of the 
perspiration is to regulate the temperature of the body. 
It is well known that when a liquid evaporates, it pro- 
duces cold. So the evaporation of a number of pounds 



168 THE ESSENTIALS OF HEALTH 

of water each day from the surface of the body during 
the warm days of summer causes a considerable lower- 
ing of the temperature. Exercise during the summer 
would be quite impossible were it not for this fact. 
The exercise causes rapid oxidation in the tissues, and 
this produces heat ; and added to this is the heated atmos- 
phere. Were not some way provided of cooling the body, 
it would soon be in a raging fever. But the more one 
exercises and the higher the thermometer, so much more 
profuse is the perspiration, while its rapid evaporation 
causes the body to remain at about a fixed degree of heat. 

Checking the Perspiration. — Sudden cooling of the skin 
checks its action, throws additional work on other parts 
of the body, and often causes disease. One of the most 
frequent causes of a cold is the sudden checking of the 
perspiration. After exercising, or whenever the body. is 
perspiring freely, great care should be taken in regard to 
draughts of air. The body should be gradually cooled, 
with some extra clothing thrown over the shoulders, while 
resting. Sudden checking of the perspiration is positively 
injurious and may easily lead to fatal results. 

Ordinary Diseases of the Skin. — The more ordinary 
diseases of the skin are the hives, heat rash, eczema, acne, 
and the itch. 

The hives, or nettle rash, is often caused by some dis- 
turbance of the digestion. The skin becomes very red, 
and there is great burning and itching. Sometimes the 
eruption is in small spots distributed. over the body, or it 
may take the form of an even rash over a portion of the 
body. Some persons cannot eat clams, lobsters, oysters, 
or any kind of fish, Avithout having an eruption of the 
skin. Others cannot eat strawberries without bringing 
on such an eruption. Usually this is a very simple 



THE SKIN 169 

disease and passes away as soon as the cause is removed. 
A gentle laxative, such as a seidlitz powder, is generally 
all the treatment that is necessary. 

Heat rash, or prickly heat, is an affection of the sweat 
glands of the skin. It is generally caused by exposure to 
extreme heat, by working in an overheated room, or from 
wearing too heavy clothing in hot weather. This is not 
a serious disease, and, when the cause is removed, it 
does not ordinarily require treatment. 

Eczema is more familiarly known as tetter, or salt 
rheum. At first there is only a small red spot, or a 
number of these spots arranged in clusters. The skin 
itches and burns, and soon scales are formed over the 
inflamed places ; there may be a large surface inflamed in 
this way. The disease has a tendency to become chronic 
unless promptly treated, therefore a physician should 
always be consulted with reference to it. 

Scabies, or the itch, is a highly contagious disease. It 
is caused by the presence of minute animals that have 
penetrated just beneath the surface of the skin. By their 
presence they produce an irritation which causes most 
intense itching, especially between the fingers. The 
disease may extend all over the body, and the itching 
may become severe enough, when the body is warm in 
bed, to prevent sleep and to cause great discomfort. 
This disease may be completely cured, but the services 
of a physician are necessary. 

Acne is another disease of the skin which is very 
common among young people. It consists of minute 
pimples, in the center of which there is usually a little 
yellowish matter. Acne is generally due to some dis- 
turbance of the digestive system, hence in order to make 
the cure complete careful attention should be paid to the 



170 THE ESSENTIALS OF HEALTH 

diet, and to all the general rules of health. Each pimple 
should have its contents removed by pressing it carefully 
with the fingers, which have first been carefully cleansed, 
or with some blunt instrument. When there are black- 
heads it is quite necessary that these be removed if the 
cure is to be prompt and permanent. The best local 
treatment for a face in this condition is to wash it with 
very hot water for five or ten minutes, morning and night. 
Cold water should be next applied, and then the face 
should be thoroughly dried with a soft towel. During cold 
weather it may be best to use the hot w^ater only at night. 

Shingles is a disease which consists of a rash, extending 
in a circular manner halfway around the waist. The 
skin burns and smarts, and the general system is often 
more or less affected. It is a disease that requires the 
services of a physician. 

There are diseases caused by very low forms of vege- 
table life, called ringworm, scald head, and barber's itch. 
These vegetable growths can be seen with only the very 
high powers of the microscope. All these diseases are 
very contagious, and should be promptly treated by a 
competent physician. 

The Hair. — A hair consists of the root and the shaft. 
The former is situated in the skin, and the latter projects 
from it. The hair may be easily removed from its sac or 
follicle, without damage. At the lower end of each hair 
follicle is a small eminence, or papilla, which is well sup- 
plied with blood vessels. The root of the hair rests on 
this papilla and grows from it. The cells of the papilla 
multiply and grow, pushing those already formed upward 
toward the surface. A hair, therefore, grows entirely 
from the root, from this minute papilla. If a hair is 
removed, another begins to grow at once from the papilla, 



THE SKIN 



171 



and in time will appear on the surface. Only a destruc- 
tion of the papilla can prevent the hair from growing. 

The hair shaft is not hollow, although its center is com- 
posed of cells more loosely arranged than those forming 
the exterior. Hair is very elastic ; with proper care it 
can be made to stretch nearly one third its entire length 
before breaking. It is also very strong, — a single hair 
being capable of suspending a body weighing from three 
to five ounces. 

A glance at Figs. 75 and 76 shows that the microscope 
reveals a great difference between the hairs of the lower 
animals and those of man. 
In certain cases the differ- 
ence is very marked, as here 
shown, while in others it is 
not so marked. 

Muscle of the Hair. — In 
Fig. 73 it is noticed that 
the hair is placed obliquely 
in the skin. Fastened to 
the lower part of each hair 
sac, and extending obliquely 
upward and to the left, is a 
minute bundle of involuntary muscle. This muscle is 
better shown at M, in Fig. 77. The muscle is thus 
arranged at an acute angle, so that when it contracts, 
it pulls on the base of the hair sac, causing it to stand 
more nearly erect. In this way the hair is made literally 
"to stand on end." A contraction of this muscle pro- 
duces the condition known as "goose skin." 

The Sebaceous Glands. — The sebaceous or oil glands 
are situated by the side of the hair sacs, into which they 
open by a duct, as illustrated in Fig. 77 at G. These 





Fig. 75. — A human 
hair, magnified. 



Fig. 76. — A cat 
hair, magnified. 



172 



TEE ESSENTIALS OF HEALTH 



glands secrete an oily substance which is spread around 
the hair, making it smooth and glossy. Some of the 
secretion extends over the skin, making it soft. Often 
the ducts to these glands become stopped up, and. the 
secretion distends the glands, forming " black heads." 

Care of the Hair. — In the case of boys, the head should 
be washed once a week with soapy water, and then thor- 
oughly rinsed with clear water. 
Then rub the head thoroughly with 
a towel until the head and the hair 
are both perfectly dry; if this is 
done, there need be no fear of tak- 
ing cold. As girls have hair that 
is longer and heavier, it cannot be 
dried so easily ; hence they cannot 
well wash the scalp so frequently. 
The Nails. — The nails grow 
from behind forward, thus being 
constantly pushed outward. They 
protect the ends of the fingers and 
toes, and give aid to the fingers 
in picking up small objects. If 
a nail be removed, a new one will 
take its place in a few weeks, pro- 
vided the root is not injured. 
Care of the Hands. — Great care 

Fig. 77. — A human hair in , , -. , n - , . ,, -. , 

its sheath, or follicle, magni- should be used that the hands are 

fied : H, the hair shaft ; M, the kept as clean and neat as possible 

muscle; G, the oil gland. ftt ftU ^^ Thig ^^ ^ tQ 

the nails. The finger nails should be kept neatly trimmed, 
and should always be perfectly clean. Biting the nails 
injures their shape and is disagreeable to the witnesses. 




CHAPTER XIX 
BATHING — CLOTHING 

Necessity of Bathing. — We know that an immense num- 
ber of sweat glands are constantly pouring their secre- 
tion on the surface of the skin ; that vast numbers of oil 
glands are depositing an oily substance on the surface 
also ; and that the cells of the epidermis are constantly 
loosening and falling off in great numbers. It is only 
necessary to recall these facts, in order to understand 
fully the necessity of frequent bathing. The glands of 
the skin have a certain work to do ; how can they prop- 
erly perform this if their ducts be closed by an accumu- 
lation of such material on the surface ? If these glands 
cannot perform their full duty, then other glands or 
organs must do it for them, or sickness will follow. 

Always considered Important. — The nations of antiquity 
had much to say about the bath, both as a luxury and as 
a means of preserving the health. The public baths of 
Rome were among the most interesting of her works of 
grandeur and beauty. Most beautiful works of art have 
been recovered from their ruins, all speaking of the 
splendid preparations made for the bath. The price 
charged for a bath in these elegant quarters was very 
low, so that all of the people could enjoy its benefits. 
After bathing, the skin was usually anointed with per- 
fumed oil, and this was followed by light exercise for a 
short time. In those days nearly every one could swim ; 

173 



174 THE ESSENTIALS OF HEALTH 

and to be unable to swim was about as great a disgrace 
as to be unable to read. 

When to Bathe. — Probably immediately after rising 
in the morning is the best time to bathe. The body is 
rested, reaction is easy, and the circulation is at its best. 
The ideal daily bath is a cold sponge bath taken im- 
mediately after rising, followed with a brisk use of the 
towel. One should never bathe when greatly fatigued, 
nor use a cold bath if feeling chilly. Neither should a 
bath be taken immediately before or immediately after a 
hearty meal. It should not be taken soon after a meal, 
because the rubbing brings the blood to the surface, and 
therefore must take some of the blood away from the 
stomach, where it is needed. Great caution should be 
used in bathing when the body is overheated, and when 
it is perspiring freely ; because if the water should be too 
cool, or if the rubbing should fail to produce a complete 
reaction, then a severe cold or something more serious 
might result. Avoid both water that is too cold and 
water that is too hot. 

The Cold Bath a Tonic. — A healthy person should re- 
gard the bath as something more than a cleansing pro- 
cess. It should be a tonic of the most invigorating 
character. The first effect of the cold is to drive the 
blood from the skin ; but soon reaction takes place, and 
the blood returns with renewed force, filling the capil- 
laries of the skin, and imparting a healthy glow to the 
entire surface. Just at this time the bathing should 
cease. The brisk use of the towel heightens the flow 
of blood, and the whole body becomes enveloped with 
a pleasant sense of comfort and warmth. To remain 
longer in the bath would be to send the blood from the 
surface for the second time, from which reaction might 



BATHING CLOTHING 175 

not occur, causing a sensation of chilliness and fatigue. 
The brisk work of the rubbing causes the exercise of 
many muscles, and the whole body is thereby aroused 
to activity. 

The cold bath is injurious to those who do not have 
a quick reaction from its use. The skin should be left 
red and warm, and the whole system ought to be invig- 
orated. Jf not, and if the opposite be true, then the 
cold bath is injurious rather than helpful. If the bath be 
short at first, if the water be cool, if it be continued daily, 
if the towel be used briskly, and if only a portion of 
the body be bathed at a time, then it must be of benefit. 
Soon the water can be used colder and the time of the 
bath extended. With these precautions in mind, it is 
safe to assert that there are very few young people, in fair 
health, who would not be greatly benefited by the daily 
use . of the cold bath. A quick sponge bath with cold 
water, followed by thorough rubbing, is the best method 
to illustrate the advantages and safety of the cold bath. 

Salt-water Bathing. — Many persons who visit the sea- 
shore plunge into the cold water at once, and remain 
there for a number of minutes. If they have been accus- 
tomed to the cold bath at home, there can be no more 
healthful exercise. The beating of the surf against the 
skin is an invigorating tonic in itself, while the muscles 
of the whole body are brought into action in withstand- 
ing the force of the waves. The change of scenery and 
the freedom from care aid in imparting new life to the 
seaside bather. If he be unaccustomed to the cold bath, 
however, and suddenly begins to spend from twenty to 
thirty minutes in the sea, he must expect undesirable 
effects to follow. A vast amount of sickness is caused in 
this way, which might be prevented. 



17(3 THE ESSENTIALS OE HEALTH 

Other Forms of Baths. — A Turkish bath is one in 
which the bather is placed successively in rooms of in- 
creased temperature ; then rubbed ; and, at last, douched 
with cold water. For a Russian bath, the person is 
placed in a room in which steam is escaping from a 
steam pipe ; this is followed by brisk friction of the body. 
In taking a shower bath the water strikes the body in a 
number of small streams. A bath is cold when the tem- 
perature of the water is from 60° to 75° F. ; a tepid bath 
is from 85° -to 95°; a warm bath, from 90° to 104°; a hot 
bath, from 104° to 110°. 

It is a great mistake to suppose that one needs to take 
an alcoholic drink of any kind after bathing, to prevent 
taking cold. The notion, however, is a prevalent one, 
especially as regards sea bathing. 

A warm bath once or twice a week, with the use of 
pure soap, is necessary. But a daily warm bath, in the 
bath tub, lowers the tone of the system and diminishes its 
power to withstand disease. 

How to Bathe. — There is always a temptation to have 
the bath tub filled with tepid water, and then to remain 
in it a long time. But this method deprives the bath of 
its tonic properties. A bath of this description once a 
week may be desirable, but is most undesirable for daily 
use. The better method is to use the hands, or mittens 
made from crash toweling; quickly cover a portion of 
the body with cool or cold water ; rub this portion dry ; 
and thus proceed until the bath is completed. The whole 
bath should not exceed five minutes. 

The Value of the Bath. — The value of the bath will 
depend largely on the completeness of the reaction fol- 
lowing its use. As stated before, the skin should be 
warm and the whole system refreshed. But if the skin 



BATHING — CLOTHING 177 

be cold, and the body feel chilly and fatigued, or if the 
bath be followed by headache and general lassitude, then 
the practice should be discontinued, and a physician con- 
sulted to discover where the error rests. The bath is 
of great value to those who are already well and strong ; 
it is to such that its use is so freely recommended. It is of 
great value in keeping the various organs and tissues of 
the body in a healthy condition, and it is therefore a good 
preventive of disease. The aged and the feeble need 
special advice for their particular cases ; and the bath 
should be used by them under the advice of a physician. 

A Good Complexion. — Bathing is essential if one desires 
a good complexion. The skin must be active and do its 
part of the work. Frequent bathing of the face with pure 
water is especially desirable. Little soap is necessary 
for the face; its use often causes roughness of the skin. 
Cosmetics almost invariably contain substances which are 
injurious to the skin. 

The Clothing. — One object of the clothing is to prevent 
too great loss of heat from the body. The surrounding 
atmosphere is nearly always cooler than the body, there- 
fore there is a tendency for the body to lose heat. The 
clothing corrects this tendency in a large measure. Food 
maintains the heat, and the clothing prevents its escape ; 
for this reason it is true that poorly fed persons need more 
clothing in winter than those who are well fed. Animals 
require less food, and are able to do more work, if they 
are kept warm during the cold weather. 

Adaptation of Clothing. — Our clothing should be suit- 
able to the season, and to the time of day. To escape the 
effects of sudden changes of temperature, the garments 
worn next the skin should be made of a material which 
is a poor conductor of heat. Any change from thick to 



178 THE ESSENTIALS OF HEALTH 

thinner garments should be made in the early part of the 
day, as the evenings are usually cooler and the body is 
more fatigued at night. More clothing is necessary dur- 
ing sleep because the temperature of the air is colder than 
during the day, and the body is inactive. A person who 
is exposed to the direct rays of the sun, should consider 
the color of the clothing. White is the best protection ; 
then, in order, gray, yellow, pink, blue, and black. 

Sources of Clothing Materials. — Our woolen clothing is 
made from the wool of sheep. In the western part of our 
own country the sheep growing industry is very large. 
In Australia, which is a great sheep raising country, a 
single flock often contains hundreds of thousands of sheep. 
After the wool is sheared off, it is thoroughly cleansed, 
then spun into yarn, and then woven into cloth. 

Linen is made from flax. Certain parts of the stalk of 
the flax are removed and prepared in such a way that it is 
easily spun into thread ; afterwards the thread is woven 
into cloth. 

The cotton cloth with which we are all so familiar is 
made from the cotton plant which is grown so largely in 
our southern states. The cotton is spun into thread, and 
then woven into cloth, as is the case with linen and wool. 

The Choice of Clothing. — Furs are extensively used 
during the cold weather. It is not wise, however, to wrap 
furs close around the throat. They make one much more 
liable to take cold, and they weaken and debilitate the 
throat. To be sure, in severe storms, or during unusual 
exposure, they may be so worn, but as a regular practice 
they should not be wound around the throat. 

Next to fur, wool is the most suitable and hygienic 
material for winter clothing. All woolen garments are 
poor conductors of heat, and are therefore valuable for 



BATHING CLOTHING 170 

winter use. Garments that have coarse meshes are the 
best protection against the cold in winter, and the sudden 
changes in summer. They should be worn next to the 
skin the entire year. 

Some simple precautions in dress would prevent an im- 
mense amount of illness. The sudden changes in tem- 
perature and exposure to draughts would not so often be 
followed by colds, chills, sore throats, and lung troubles, 
if the body were constantly covered by clothing that 
constituted a non-conducting medium. Cotton is to be 
preferred to linen for bed clothing. The outer garments 
can be regulated according: to the seasons. 

Wet Clothing should be Changed. — Wet feet are the 
cause of many a sore throat and severe cold ; and for most 
persons, it is a great risk to allow the feet to remain damp. 
They should be dried and rubbed thoroughly as soon as 
possible, in order fully to restore the circulation. If one is 
caught in a storm and the clothing becomes damp or wet, it 
should be changed at the first opportunity. Brisk exercise 
in the meantime will keep the body from becoming chilled. 

When a Cold Starts. — When a cold first comes on, all the 
blood leaves the surface of the body, causing the skin to 
become cold and inactive. At this early stage, a cold may 
frequently be broken up. The object is to bring the blood 
back to the skin as soon as possible. This is best done by 
taking a cupful of some hot drink, such as hot lemonade, 
or hot ginger tea, at the same time putting the feet in hot 
water. Do this just before retiring, and in winter time 
have the bed warm so that the body may not be chilled. 

Tight Lacing. — Tight lacing is very injurious, and 
produces a figure that is far from being attractive. It 
interferes with the free action of the chest, and prevents 
the blood from getting its full supply of oxygen. 



CHAPTER XX 
ANIMAL HEAT 

Sources of Animal Heat. — It has already been stated 
that the heat of the body is derived from the food, and 
from the oxygen obtained during respiration. By the 
union of these oxidation occurs and heat is produced. 
This shows that there must exist a relation between the 
amount of oxygen consumed and the amount of heat 
produced in the body. Another source of heat is from 
certain physical processes of the body, as the work of the 
heart, the general circulation, and the active exercise of 
the body. 

The chief source of heat is found in the muscular 
system. The muscles form a large proportion of the 
whole frame, and they are very active during many hours 
of the day. The greater their activity, the more rapidly 
will the tissue be exhausted, and new tissue take its place. 
These changes require the oxidation of much food,' and 
thereby much heat is developed. Next to the muscles as 
heat producers are the secreting glands. Most rapid 
changes occur in these glands when they are active, all 
of which produce heat. The liver is the most important 
gland in producing heat, the changes taking place in the 
liver cells being very active and continuous. The warm- 
est blood in the body is found just as it leaves the liver, 
on its way to the heart, being much warmer here than 
when it enters the liver. But heat is generated in every 

180 



AMMAL HEAT 



1K1 



organ and tissue in the body, since every activity contrib- 
utes to an elevation of the temperature. 

Temperature of the Body. — The thermometer (see 
Fig. 78) shows that different parts vary in temperature. 
In those parts where rapid changes are taking 
place, and where oxidation is most marked, 
the temperature is higher than the average 
for the body. The blood is constantly passing 
from one tissue to another, carrying warmth 
from the tissues where heat is being developed 
to other tissues where it is being lost ; thus 
the blood tends to equalize the temperature of 
all parts of the body. The temperature is 
generally ascertained by placing the bulb of 
a thermometer under the person's tongue. 
The loss and production of heat are so evenly 
balanced that the temperature of the healthy 
adult body varies little from 98^-° F. This is 
maintained with only slight variation through- 
out life. So accurately is this adjusted dur- 
ing health that a variation of more than a 
single degree denotes some disturbance in the 
system ; a fall of two degrees below the nor- 
mal temperature is considered a serious matter; 
while a severe cold may cause it to rise two 
degrees above normal. A temperature above temperature 
103° denotes a high fever; of 105°, a severe of the healthy 
attack ; above 105° is most alarming ; while 
recovery after the temperature has reached 110° is very 
rare. 

The normal temperature of 98J° F. is subject to some 
variations within narrow limits. There are quite regu- 
lar variations in the course of every twenty-four hours. 



Fig. 78. — 
Clinical ther- 
mometer: the 
mark indi- 
cates 981° F., 
the normal 



182 THE ESSENTIALS OF HEALTH 

The temperature continues to rise during the da} 7, until it 
reaches the highest point from five to eight in the even- 
ing ; then it continues to fall during the night until from 
two to six in the morning, when it is at the lowest. 
About the middle of the forenoon, or about three hours 
after the morning meal, the thermometer should record 
98^° F. The difference between the lowest and highest 
points reached during the day usually does not exceed 
one degree. 

The Regulation of Heat. — The question now arises, 
How is the excess of heat above 98^° removed from the 
body? The body would soon become very much warmer 
were not some means provided for regulating the heat. 
It is estimated that an adult body produces, in one hour, 
enough heat to raise the temperature three degrees. If 
no heat were given off, in thirty-six hours the temperature 
would reach the boiling point ; hence the distribution 
and removal of the excess of heat becomes an important 
matter. 

The two principal tissues which regulate the tempera- 
ture are the lungs and the skin. It has been stated that 
the expired air is warmer than the inspired air. There- 
fore considerable heat is evidently carried out of the body 
with each expiration. The evaporation of the water of 
the expired air — the watery vapor — also produces cold; 
in fact, the loss of heat is in definite proportion to the 
amount of air taken into the lungs in a given time. 
The rapid breathing of a dog after running and the 
extra flow of water from his mouth are illustrations of 
these facts. 

But the work of the skin is far more important, being 
five times as great as that of the lungs in this particular. 
It must be evident that the more freely the blood passes 



ANIMAL HEAT 188 

through the skin, thus coming under the influence of the 
cooler surroundings of the body, so much the greater will 
be the loss of heat. The evaporation of the perspiration 
results also in a great loss of heat to the body. 

This regulation of the heat is well illustrated by 
studying the changes which take place during active 
exercise. Muscular contraction gives rise to heat ; hence 
exercise must increase the bodily temperature. But the 
thermometer shows no such change ; what then becomes 
of the heat thus produced ? The exercise causes rapid 
breathing, and hence more loss of heat through the 
lungs ; while more blood is sent to the skin, where its 
temperature is lowered. The exercise also causes the 
skin to perspire freely, and the evaporation of the water 
from the surface of the body results in a great loss of 
heat. Thus we find that the extra amount of heat 
caused by muscular exertion is thown off by the increased 
action of the lungs and skin ; and as a result, the 
temperature of the body remains at a fixed point. 

Effects of Lowering the Temperature. — The body is 
warmed by heat generated within itself. To lower its 
temperature, it is only necessary to abstract the heat 
faster than it can be produced. The first effect of this 
is pain in the more exposed parts. The face and ex- 
tremities "ache with the cold.' 1 This soon passes away 
and the skin becomes quite insensible. The testimony of 
persons who have been rescued from freezing, even after 
they were insensible from the cold, is that an inclination 
to sleep overtakes them soon after the pain has left the 
skin ; the muscles become inactive ; breathing is slow and 
difficult ; and the whole nervous system becomes sluggish. 
Finally, the desire to sleep becomes irresistible, and in a 
short time death ensues. In the case of those who have 



184 THE ESSENTIALS OF HEALTH 

been rescued from a freezing condition, it has been found 
that the respiration is hardly perceptible, the heart's 
action extremely weak, and all the functions of the body 
nearly suspended. 

The above condition is very similar to that of the so- 
called hibernating animals. These animals go to sleep at 
the approach of winter, and do not waken until the com- 
ing of spring. When found, buried in their nests, or deep 
underground, they are quite insensible and immovable. 
Their respiration is hardly discernible, and their bodily 
temperature is much reduced. The oxidation of tissue 
is very slight, and the animal appears to live by using 
up its own flesh, — entering upon sleep well supplied with 
fatty tissue and awakening in the spring very thin and 
poor. 

Effects of Raising the Temperature. — When the animal 
heat is raised a number of degrees, as in fevers, the 
effects are quite the reverse of those produced by cold. 
In fevers, the pulse and the respiration are increased in 
frequency, and instead of a feeling of comfort and sleep, 
there is often much distress and wakefulness. Increased 
temperature appears to hasten the normal changes taking 
place in the tissues ; oxidation is more rapid, the tissues 
are more quickly exhausted, and the vitality is lowered. 

Winter and Summer. — The moderate cold of winter 
imparts a feeling of vigor and stimulates the whole system. 
The cool air excites a desire to run, and to exercise the 
whole body ; this activity adds to the amount of heat 
which is necessary to resist the cold. Without exercise, 
the internal heat must be preserved by additional clothing, 
or the depressing effects of cold will be experienced. Cold 
weather brings a good appetite ; the extra amount of 
food is so much more fuel, contributing to the maintenance 



ANIMAL HEAT L85 

of the animal heat ; thus we learn that a healthy body 
always demands more food during the winter than during 
the summer. Muscular activity, extra clothing, and more 
food enable the body to resist the cold and still maintain 
its average temperature. During the heat of summer less 
food is required and more liquids are used, the perspiration 
is increased, and the clothing is lighter, all of which tend 
to diminish the supply of heat and to increase the means 
for its escape. 

The Effects of Alcohol on Temperature. — The feeling 
that alcohol warms the body is among the deceptions that 
follow its use. What it does do is to cause the minute 
blood vessels of the skin to become distended and an in- 
creased amount of blood to flow to the surface of the 
body. The blood as it comes from the interior is warmer 
than that near the surface ; therefore, when an extra 
amount flows to the surface at one time, it makes the skin 
feel much warmer. Jt is this that makes the person feel 
warmer, but in reality he is losing heat ; for an unusual 
amount of heat is being given off by the blood at the 
surface. 

The period during which the skin feels warmer is very 
brief, while the period of cold following is of much longer 
duration. During the second period there is a fall of 
temperature proportionate to the amount of alcohol taken 
and the degree of cold to which the person is exposed. If 
the amount taken is sufficient to cause prolonged sleep, 
there may be a considerable reduction of temperature. 
In normal conditions, when a person is exposed to unusual 
cold, the blood vessels of the skin contract, allowing less 
blood than usual to approach the surface and become 
cooled. The action of alcohol interferes with this pro- 
vision of nature. 



186 THE ESSENTIALS OF HEALTH 

Explorers in Arctic regions and travelers in cold 
countries are perfectly agreed that alcohol increases the 
suffering and danger from exposure to extreme cold. 
Their testimony is all to the effect that the use of alcohol 
in cold countries is extremely hazardous. The same 
principle applies to exposure to unusual cold in more 
temperate climates, and shows the fallacy of drinking 
alcoholic liquors to " warm one up," or to aid in keep- 
ing one warm on a cold day. They only make exposure 
to cold more dangerous. The men who never use alcohol 
bear such exposure much better and do their work more 
easily than those who take it. 

Dr. J. Johnson, the Honorary Physician to Bolton Infirm- 
ary, England, says : " The verdict of medical science is em- 
phatic enough, for it tells us that alcohol is in no real sense a 
food, and that the idea that these drinks strengthen the body 
is a complete fallacy. This is confirmed by the practice of all 
our great athletes, — swimmers, wrestlers, 6 strong men/ boat 
racers, scullers, runners, cyclists, cricketers, and the most 
sensible f oot-ballers, — who all train without alcohol, and ab- 
stain from it before and during the performance of their feats. 
Why? Because they know that it is a broken reed to trust 
to, a false friend, who is sure to fail them in their hour of 
need. . . . Every cyclist knows that he can go farther and 
faster without alcohol than with it, and that beer, often a 
single glass, will i take the steam out of him.' " 

Dr. E. Stuver states : " Alcohol lowers muscular force and 
efficiency. This is conclusively shown by the fact that those 
who engage in athletic sports must stop drinking if they ex- 
pect to excel. No prize fighter, ball player, oarsman, or any 
other kind of athlete can keep up drinking habits without so 
injuring himself in a few years that he is relegated to the 
rear as a back number." 



CHAPTER XXI 
THE ANATOMY OF THE NERVOUS SYSTEM 

Two Systems. — The nervous system consists of two 
great parts, the cerebro-spinal system and the sympathetic 
system. Each system has its nerve fibers and cells, and its 
collections of nerve cells, called nerve centers. Although 
these two great systems have their independent work to 
do, yet they are closely connected by many delicate nerve 
fibers. 

The Cerebro-spinal System. — The cerebro-spinal system 
is composed of the brain, the spinal cord, and the nerves 
which originate from them. The brain and the spinal 
cord are the great nerve centers of the body. They are 
connected with the nerves of the special senses and with 
the nerves of common sensation ; they convey to the 
mind the sensations of taste, touch, sight, smell, and hear- 
ing, as well as the sensations of pain, hunger, and thirst. 
The mind, in turn, expresses itself through them. Through 
the cerebro-spinal system the commands of the mind are 
conveyed to various parts of the body ; thus, we " will " 
to move a muscle ; instantly a command is sent along 
the nerves of this system to the proper muscle, and it 
promptly obeys (Fig. 79). 

The Sympathetic System. — The sympathetic or gan- 
glionic system consists of a number of ganglia and nerve 
fibers. The ganglia may be very small, composed of only 
a few cells, and visible only under the microscope; or 

187 



188 



THE ESSENTIALS OF HEALTH 



they may be large enough to be seen with the unaided 
eye. These ganglia are placed at the sides and front of 
the whole length of the spinal column. They are joined 

together by means 
of nerve fibers. 
Nerve fibers also 
connect these gan- 
glia with the brain 
and spinal cord. 
Other nerves pro- 
ceed from these 
same ganglia to all 
the organs in the 
thoracic and ab- 
dominal cavities. 

The sympathetic 
nerves do not go 
to the skin, neither 
are they connected 
with the special 
senses, nor are 
they under the 
control of the will. 
This system pre- 
sides over the in- 
voluntary processes 
of the body ; such 
as the circulation, 

Fig. 79. — A diagram of the cerebro-spinal system. , , , . ,. , , 

the digestion, the 
respiration, the absorption, the nutrition, and the invol- 
untary muscles. It also controls the secretions of glands, 
and has much to do with the amount of blood distributed 
to the various organs and tissues. . 




THE ANATOMY OF THE NERVOUS SYSTEM 189 



Nerve Tissue. — There are two kinds of nerve tissue. 
Both are found in the cerebro-spinal and in the sympathetic 
systems. One tissue is composed of nerve fibers, and the 
other of nerve cells. The presence of numbers of the nerve 
cells gives a gray color to the tissue, while the nerve fibers 
appear white. Hence, an accumulation of nerve cells is 
called the gray substance, and a collection of nerve fibers is 
called the white substance. The nerve cells represent the 
centers of activity from which the orders are issued. The 
nerve fibers are simply the conductors, conveying the mes- 
sages from place to place. The gray substance, therefore, 
represents the seat, or 
origin, of the mysterious 
forces of the nervous 
system ; while the white 
substance represents 
only so many fibers for 
the transmission of the 
forces. 

The Nerve Cells. — The 
greatest collection of 
nerve cells is found in the gray matter of the brain, the 
next in the spinal cord, and the next in the ganglia of the 
sympathetic system. Nerve cells generate nerve force. 
They also receive it from other cells and give it out 
again. They are therefore generators and transmitters of 
nerve force. 

The cells vary exceedingly in size and shape. Some 
are of a circular form, as at the upper left corner of Fig. 
80. Others have a long process extending from them, as 
shown in the cell to the right of the circular cell. This one 
process represents the beginning of a nerve fiber, so that 
nerve force originating in the cell can be conveyed from it 




Fig. 80. — Various forms of nerve cells, 
highly magnified. 



190 THE ESSENTIALS OF HEALTH 

through this fiber to some distant organ or tissue. Other 
cells have many processes, only one of which conveys nerve 
force to the distant parts. 

The Nerve Fibers. — The nerve fibers convey impres- 
sions to their nerve centers. If the end of a nerve fiber 
is affected (as, for example, when a finger is touched), a 
vibration is set up in the nerve fiber, and by this vibration 
the report of what has happened is conveyed along the 
nerves to the proper nerve center, which may be in the 
brain, or in the spinal cord. There the report thus sent 
is acted upon in some way ; it may be that an order is 
sent by the brain over another line of nerves to a set of 
muscles in the hand, telling them to pull the hand away 
from the object touching it. All this happens rapidly ; so 
fast, indeed, that it seems to be instantaneous. 

Two Kinds of Nerve Fibers. — To understand better this 
action of the nerves, compare the nerves and the telephone 
system as we see it in daily operation. In many ways 
they work alike. There is one important point of differ- 
ence : a message may be sent over a telephone wire in either 
direction ; it is not necessary to have one wire over which 
to talk to Central and another wire over which Central 
can reply. In the case of the nerves, two complete sets of 
nerve fibers, or wires, are required. One set conveys sen- 
sation from the outer parts toward the nerve centers ; while 
the other set conveys instructions from the nerve centers 
outward to the muscles. 

The first set is composed of nerve fibers called sensory 
fibers, because they convey sensations to the spinal cord 
and brain; the other set consists of fibers called motor 
fibers, because they convey the stimulus of motion from 
the brain and spinal cord to the muscles. So far as is 
known there is no difference in the structure of these 



THE ANATOMY OF THE NERVOUS SYSTEM 191 

fibers, and as a rule they are side by side throughout the 
body. 

A nerve, as seen in the body, consists of a large number 
of these nerve fibers held together by a delicate connective 
tissue. Each nerve fiber extends the whole length of the 
nerve, from its beginning in the brain, or spinal cord, to 
its termination. 

The Brain. — The brain is situated in the cranial cavity, 
or the skull. It is surrounded by three distinct mem- 




Fig. 81. — Side view of the whole human brain : (1) cerebrum ; 
(2) cerebellum ; (3) medulla. 



branes, of which the middle one is capable of secreting a 
fluid. The membranes protect the brain from friction 
against the bony walls, while the watery secretion gives it 
some slight freedom of motion and protects it from the 
effects of jars or of concussions from without. The brain 
is well supplied with blood by large arteries entering at 
the base of the skull. 



192 



THE ESSENTIAL* OF HEALTH 



The weight of the brain depends partly upon the size 
of the individual, and partly upon his intellectual capacity. 
The average weight of the brain of an adult male is a trifle 
over three pounds, 49J or 49| ounces. The brains of idiots 
are very light, weighing from twenty-seven ounces to as 
low as eight ounces. 

The brain is divided into the cerebrum, the cerebellum, 
and the medulla oblongata. 

The Cerebrum. — The cerebrum is the brain proper. It 
is the part above the ears, and is familiarly known as the 

great brain. It is believed 
that the cerebrum is the organ 
of the mind ; that it is here 
we think, know, and reason. 
The cerebrum is divided into 
two parts by a natural fissure 
which passes from the front 
backward. At the bottom of 
the fissure, the two parts are 
united by a band of nervous 
tissue. From this it would 
at first appear that we have 
two brains corresponding to 
the right and left sides of the 
body ; but doubtless the band 
of union between them not 
only connects the structure of the two, but also in some 
way unites their functions. 

Figs. 81 and 82 show that the surface of the human 
brain is not smooth, but is thrown into a number of ridges 
or convolutions. The brains of many animals also have 
ridges, but the number of convolutions, and the depth to 
which they reach, varies in the different animals. In 




Fig. 82. — The human brain, 
viewed from above : only the cere- 
brum is seen, with its deep fissure 
nearly dividing it. 



THE AX ATOMY OF THE NERVOUS SYSTEM 193 



some, the surface is perfectly smooth, as in the fishes, 
reptiles, and birds (Fig. 83) ; in others, the convolutions 
are shallow and few in number; in man, they are many 
and very deep. It is reasonable to suppose that the gray 
matter alone of the brain is connected with the intelligence 
of the animal. This is difficult to prove ; but as a rule, 
the more intelligent the animal, the more numerous and 
the 'deeper are the convolutions of the cerebrum. 

Gray and White Matter of the Cerebrum. — The gray 
matter is on the outside of the brain ; the white matter is 
within, forming the center of 
the brain. The white matter 
is raised in slight folds on its 
surface to form the center 
of the convolutions ; but the 
bulk of the convolutions is 
formed by the gray matter. 
It has already been stated 
that the gray matter consists 
principally of nerve cells, and 
that these cells are the active 
agents in originating, receiv- 
ing, and sending forth orders. 

The Cells command, and the both viewed from above. There are 
fibers Obey; the cells Origi- no convolutions on the cerebrum. 

nate, and the fibers carry the messages. Since the cells 
are specially concerned in originating and commanding, 
it is evident that a large amount of the gray matter is 
most desirable. 

The convolutions provide for this extra amount of gray 
matter. This is made clear by the diagram in Fig. 84, 
Suppose the surface of the brain were smooth, and cov- 
ered with a layer of gray matter, then the line from 




Fig. 83. — (1) The brain of a 
pigeon ; (2) the brain of a frog, — 



194 



THE ESSENTIALS OF HEALTH 



A to B would represent the extent of the surface. But 
when the layer of gray matter is thrown into folds, or 
convolutions, then the amount of surface is represented 
by the line 1 to 2. It is at once clear that the line 1 2 
is much longer than the line A B. In other words, the 
convolutions greatly increase the amount of gray matter. 
It follows, therefore, that the deeper the convolutions and 
the greater their number, the more gray matter there will- 
be. This anatomical fact may explain why some small 
brains are more intellectual than others which exceed 




Fig. 84. — A diagram illustrating that the convolutions of the brain 
give more surface for the gray matter. 

them in size. There is another fact that may help to 
explain this seeming contradiction. The power of the 
brain can be increased by training and exercise, much as 
the muscular power can be increased. There may also be 
differences in the quality of brain material, though little 
is yet known about this. 



The Cranial Nerves. — There are twelve nerves given off from each 
side of the brain, each nerve supplying some part of the body on the 
right or left side. 

One nerve, the olfactory, goes to the nose, and is the nerve for the 
sense of smell. 

Another nerve, the optic, goes to the eye, and is the nerve for the 
sense of sight. 

Another nerve, the auditory, passes to the ear, and is the nerve for 
the sense of hearing. 

Still another nerve, the pneumo gastric, or vagus, supplies the larynx, 
lungs, heart, stomach, intestines, and liver. It is an important, 




PLATE VII 



Some of the more important parts of the nervous system : (1) cerebrum ; 
(2) cerebellum: (3) medulla; (4) spinal cord. From the lower part of the 
spinal cord a large nerve is given off, for each side of the body, called the 
sciatic nerve; it extends down the inner side of the back of the thigh (5). 
■ (6) Median nerve ; (7) radial nerve; (8) ulnar nerve: (9) pneumogastrie nerve, 
which comes from the brain. In the thoracic cavity it gives off branches to 
the heart (H) : in the abdominal cavity, to the stomach (S). 



196 



THE ESSENTIALS OF HEALTH 



large nerve, and passes down the side of the neck close to the 
carotid artery. For its location, see Plate VII. 

Some of the cranial nerves are only motor nerves, others are only 
sensory nerves, while still others are both motor and sensory nerves. 

The Cerebellum. — This part of the brain is situated be- 
neath the back part of the cerebrum, and is often called 
the lesser brain. It consists of gray and white matter 
arranged in the form of parallel ridges and furrows run- 
ning over its surface, as represented in (2), Fig. 81. 

The Medulla Oblongata. — The medulla, as it is generally- 
called, is situated at the upper end of the spinal cord, be- 
tween the cord and the brain. It represents an enlarge- 
ment of the upper part of the spinal cord, see (3), Fig. 81. 
It is well protected in the thick bones at the base of the 
skull. The functions of the medulla, such as the control 
of respiration, of swallowing, and of the action of the 
heart, are so necessary to life that it must be regarded 
as the most vital portion of the entire body ; yet it is only 
about one and one fourth inches in length. 

The Spinal Cord. — The spinal cord, as illustrated in 

Fig. 79, represents the 
elongated part of the 
cerebro-spinal system. 
It is about eighteen 
inches in length, one 
half an inch in thick- 
ness, and is nearly cir- 
cular in shape. It is 
surrounded by three 
membranes which are 
continuations of those 
surrounding the brain, and is well protected in the spinal 
canal of the vertebral column. It begins at the medulla. 




Fig. 85. — A cross section of the spinal cord 
magnified. 



THE ANATOMY OF THE NERVOUS SYSTEM 197 



and terminates at the lower end of the spinal column in a 
number of tine threads, as illustrated in Fig. 79. It is, 
like tlif brain, divided into halves by deep fissures. One 
fissure extends down the front of the cord, and the other, 
which is opposite it, extends 
down the back of the cord. 
Between them, they nearly di- St 
vide tin 1 cord into two parts. K| 
Fig. 85 illustrates these fis- % 
sures ; the one in front show- 
ing more clearly than the other. 
An open central canal is also 
seen. 

White and Gray Matter of 
the Spinal Cord. — The gray 
matter of the cord is in the 
center. It is so arranged 
that when the cord is cut 
transversely, the gray matter 
slightly resembles the letter H. 
The darkly shaded portions in 
Fig. 85 illustrate this fact, and 
it is also shown in Fig. 86. 

Outside the central gray 

matter is the white matter, Fig. 86. — Cross sections of the 
i . i -j p r»i spinal cords of different animals, 

which is composed ot libers. . , . . +1 . 

1 represented as twice the natural 

The fibers extend Up and down size: (1) horse; (2) ox; (3) man; 

the cord, so that a cross sec- W ho Z'> ©squirrel. 
tion of the cord, as seen in Fig. 85, shows the fibers to be 
circular and wdiite, with a dot or dark spot in the center. 
This dark spot represents a cross section of that part of 
the gray nerve fiber which transmits the nerve force ; the 
white substance around it is for insulation and protection. 




198 THE ESSENTIALS OF HEALTH 

These fibers finally enter the brain and are distributed to 
all parts of it, being at last connected with the nerve cells. 
The Spinal Nerves. — There are thirty-one pairs of spinal 
nerves ; each originates in the spinal cord by two roots. 
One root, the anterior, consists of motor fibers ; it origi- 
nates from the anterior part of the gray matter of the cord, 
as illustrated at (1), Fig. 87. The other root is composed 
of sensory fibers; it originates from the posterior part of 
the cord, as shown at (2). Both these roots unite to form 
one nerve, at (3). On the posterior root is a ganglion, 
(4), or a collection of nerve cells. The nerve fibers, at (3), 
continue together as a spinal nerve until they reach the 
distant parts of the body, when they separate again. Those 
fibers which originated from the anterior part, known as 
motor fibers, terminate in muscles ; while those from the 
posterior part, known as sensory fibers, terminate in the 
skin. 

The spinal nerves leave the spinal canal through openings between 
the vertebrae ; after leaving it, they divide again and again until 
their minute branches extend to all parts of the body. Should one 
of these nerves be cut or be severely injured, all power of feeling and 
of motion would cease in the parts of the body supplied by that nerve. 
We would say that the parts were paralyzed. 

The largest nerve of the upper extremities is the median nerve. 
This nerve receives its name because it extends down the median 
line, or the middle, of the whole length of the arm. Some of its 
fibers extend to the very tips of the ringers. 

The largest nerve of the lower extremities is the sciatic nerve. It 
is also the largest nerve in the body, being nearly an inch in breadth. 
It extends down the whole length of the back of each leg. 



CHAPTER XXII 
THE PHYSIOLOGY OF THE NERVOUS SYSTEM 

The Nerve Current. — We have already learned that the 
nerve fibers may be set vibrating, and that in this way 
they make their reports to the brain or the spinal cord. 
Just how this is done is not yet known ; and there is 
also much about the most common forms of vibration, 
that of a telegraph or telephone wire, for instance, that is 
not understood. We know that the vibration travels 
along the nerves at the rate of over one hundred feet a 
second. We know, too, that every form of vibration must 
be started in some way. We call the force or the agent 
that starts a vibration, the stimulus. Suppose there is a 
desire to move the hand : in this case the stimulus is an 
act of the will, which excites the nerve current, so that it 
almost instantly passes down the nerve fibers to the mus- 
cles of the arm. When the nerve current 'reaches a 
muscle, the current itself acts as a stimulus, rousing the 
muscle to action. If we pinch the skin, the stimulus is a 
mechanical one ; the sensation is carried to the nerve cen- 
ters over the sensory fibers. If a bright light is brought 
near the face, the pupil of the eye becomes smaller : in 
this case, light is the stimulus which at last causes the 
muscles of the eye to contract. A sharp scream will 
cause a person to jump ; here fright is the stimulus. 

Function of the Cerebrum. — In the cerebrum are the 
nerve currents which control our thinking, feeling, and 

100 



200 THE ESSENTIALS OF HEALTH 

willing. It is not known how the mind is connected with 
the brain, nor how the brain tissues control it; still we 
do know that if any of the nerve centers in the cerebrum 
are injured, the normal activity of the mind is interfered 
with. An injury to the head, resulting in a portion of 
the skull being fractured and pressed upon the brain, has 
been followed by loss of consciousness ; and the person 
has remained in a deep sleep until the surgeon has raised 
the depressed bone, when consciousness has returned. 

The mental state is also sometimes deranged by sick- 
ness ; for example, an inflammation of the membranes of 
the brain, affecting its surface, causes delirium and other- 
wise disturbs the mind. Medicines which affect the flow 
of blood to the brain also interfere with the reasoning 
faculties. Persons born with extremely small brains have 
little intelligence. If the cerebrum be removed, all vol- 
untary acts are abolished. Thus the evidence from the 
results of injuries, disease, drugs, and special experiments 
all show that a healthy condition of the cerebrum is neces- 
sary for the existence of intelligence and the power to will 
and to command. 

Localization of the Brain. — We have learned that the 
gray matter of the cerebrum is composed largely of cells. 
All of these cells do not act at one time for one particular 
purpose. Certain cells or groups of cells, called " nerve 
centers," act for one purpose, another group for another 
purpose, and so on. To illustrate : When we look at an 
object the brain tells us concerning it, but only a few 
nerve cells are involved in this, and these cells make up 
the "center" for sight. This center has nothing to do 
with hearing or any of the other special senses. Each of 
the special senses has its own center in the brain. There 
are also many other centers, as the center that controls 



THE PHYSIOLOGY OF THE NEEV0U8 SYSTEM 2<)\ 

the speech, and centers for the movements of the limbs. 
From this we can readily understand how some small 
part of the brain may be injured or diseased and thereby 
affect only one center. Thus, a person might be able to 
walk and think and write, but be unable to speak, because 
of trouble in the brain with the speech center. From this 
we conclude that the brain may to a certain extent be 
mapped out into spots, or places ; it may be localized. 

Two Brains. — As stated in the preceding chapter, the 
cerebrum is nearly divided into two complete parts. This 
fact has led some physiologists to declare that there are 
two brains, and that they act independently of each other. 
It is nearer the truth, probably, to say that so far as the 
mind is concerned, the two sides of the cerebrum should 
be considered as one organ, but that each side controls 
the sensation and motion of the opposite side of the body. 

Mind and Body. —In some mysterious way, the mind 
and the body are so connected that what affects the one, 
affects the other also. Experiment has shown that there 
cannot be a normal mental condition, without a normal 
condition of the cerebrum. If we would attain the fullest 
intellectual development, attention must be given to the 
laws of health, and their teachings strictly obeyed. 

Function of the Cerebellum. — Injuries to the cerebellum 
do not necessarily interfere with either the will or the 
consciousness, but they do interfere with the movements 
of the body. The cerebellum is especially concerned in 
maintaining a harmony of action of the voluntary muscles. 
By its action we are able to hold a position when taken ; 
and at all times can have the muscles act in harmony and 
with regularity. 

Functions of the Medulla. — This part of the nervous 
system is one of great interest. It is most essential to 



202 THE ESSENTIALS OF HEALTH 

life, and, as has already been stated, it controls many of 
the most important functions. In the medulla are many 
" centers " or small collections of nerve cells. When these 
centers are stimulated in any way, they put into action the 
functions they control ; as, for example, there is a " sneez- 
ing center." If some irritant be inhaled into the nose, 
the ends of the nerve fibers are irritated and an impres- 
sion is conveyed to the sneezing center ; from this center 
goes forth a nerve current to certain muscles, which con- 
tract and cause the expulsive act of sneezing. Besides the 
sneezing center there are many others, among which are 
the coughing center, the center for the secretion of the 
saliva, the swallowing center, and the center for the closure 
of the eyelids. 

One of the most important centers is known as the 
respiratory center. It is a fact that a small collection of 
cells in the medulla controls absolutely all the movements 
of respiration. This small center has greater power than 
the will itself ; for we may " will " not to breathe, and we 
may make the attempt to hold the breath, but soon we can 
do so no longer. Notwithstanding our greatest efforts, 
we again begin to breathe ; for the center in the medulla 
is stronger than the will. We may be capable of increas- 
ing or diminishing the number of respirations per minute 
for a short time, and may even cease breathing for a brief 
period ; but soon the respiratory center exerts its power, 
and respiration is continued with wonderful regularity. 

Other important centers affect the movements of the 
heart. One center continuously holds the heart in check, 
causing it to beat with great regularity. Another center 
appears to have an opposite effect at times, being capable 
of accelerating the action of the heart. 

No less important is the vaso-motor center. This con- 



THE PHYSIOLOGY OF THE NERVOUS SYSTEM 203 

trols the nerves which go to the entire arterial system. It 
is a small collection of cells, yet it is capable of causing 
the contraction, or relaxation, of the walls of any of the 
arteries. It will be remembered that in the walls of the 
arteries is a layer of involuntary muscle, arranged in a 
circular manner around the vessels ; if the muscle con- 
tracts, the vessel will be narrowed ; while if it relaxes, 
the vessel will be enlarged. The vaso-motor center pre- 
sides over the action of the muscular walls of the arteries : 
the normal condition of this center is one which keeps 
the arterial walls in a moderate state of contraction at all 
times. The center is said to keep up the "tone" of the 
arteries, thereby keeping their walls firm and strong. 
When the function of this center is checked, it releases 
its hold on the arterial walls and they relax, thus enlarg- 
ing the size of the vessel. If the blood vessels are thus 
made larger, more blood will flow through them, and the 
parts will be a deeper red in color. This is usually tempo- 
rary, but it may become permanent. 

This power of the vaso-motor center is most essential 
to the preservation of health, and even of life itself. Let 
us illustrate its daily action : the cold weather of winter 
stimulates the center so that it acts with increased power ; 
this contracts the arteries of the skin, so that the flow 
of blood through it is greatly diminished. The loss of 
animal heat is thereby diminished, as we have already 
learned. But during the summer the vaso-motor nerves 
relax their hold on the smaller blood vessels of the skin ; 
the blood flows more freely through it, and the loss of heat 
is thereby increased. 

The vaso-motor center, therefore, is capable of control- 
ling the supply of blood to any part of the body. By 
increasing its normal function, the arteries of any part are 



204 THE ESSENTIALS OF HEALTH 

made smaller and the supply of blood correspondingly 
less ; while by diminishing its normal work, the arteries 
are made larger and the supply of blood increased. From 
all this it is easy to understand that the medulla is a 
most important, as well as a most delicate part of the 
nervous system. 

It is also true that the sympathetic system has power 
to control the size of the arteries. 

Injury to the Cord. — If the spinal column were very 
severely injured at a certain point, then all communica- 
tion between the nerves below that point and the brain 
would be cut off. To illustrate : Suppose the spinal 
column w^re severely injured at the small of the back. 
Then if the feet were pinched or pricked, the pain w r ould 
not be felt by the brain, for the line of communication 
would be cut. Neither could the brain send down a 
message to these nerves to have the foot moved away 
from the thing that pinched, for the same reason. All 
parts below the injury would be partially or completely 
paralyzed. 

The Spinal Cord and Reflex Action. — The spinal cord 
is the conducting medium between the nerve fibers of the 
body and the brain. 

A second function of the cord is a reflex one. It is 
a great reflex center; its action in this respect is almost 
continuous. There are many familiar illustrations of this 
action in everyday life; tickling the foot of a person who 
is asleep causes the foot to be quickly withdrawn; this 
is purely a reflex act. The impression produced on the 
nerves of the foot is conveyed along the sensory fibers to 
the spinal cord, and from the cord it is " reflected " out- 
ward along a motor nerve to the muscles of the leg. 
The sensation produced by the tickling entered the cord 



THE PHYSIOLOGY OF THE NERVOUS SYSTEM 205 

through the posterior root of a spinal nerve, and immedi- 
ately left it through the anterior root; this involved no 
interference of the brain. This is shown in Plate VIII. 

To make a reflex act, three things are necessary : an 
unbroken sensory nerve, for connecting the point touched 
with the nerve center; a healthy nerve center; and an 
unbroken motor nerve between the nerve center and the 
muscles to be stimulated. Keflex action is partly, but 
not altogether, under the control of the will. To illustrate: 
if we inhale an irritating powder, like pepper, through the 
nose, we may be able to postpone the sneezing for a short 
time, but finally we are obliged to sneeze, and no power 
of the will can prevent it. 

Course of Nerve Current in Reflex Action. — A glance at 
Fig. 87 will make clear the course of the nerve current in 
a reflex act. At the ^^-—^ 







right, (3), is one of the 
spinal nerves. This large 
nerve consists of many fc7 
fibers which proceed to- lU 
gether until they reach ^ 
some part, as the arm. 
There some of the fibers 

, ,, -, . t Fig. 87. — A diagram illustrating the 

terminate in the skin and origiu of the spinal nerves fvom the spinal 

Others in the muscles, cord. (1) and (2) unite to form (3) , a spinal 
If the skin on the arm nerve: (D^ *he motor root; (2) is the sen- 

sory root : both originate from the gray 
be touched, the Stimulus matter of the cord. (4) is a collection of 

will be conveyed toward nerve cells - 

the spinal cord an$ will finally enter it through the sen- 
sory root, at (2). The nerve current then goes directly 
through the gray matter to the anterior or motor root, 
at (1) ; it then passes down the motor fibers, which are 
alone at (1), but which are soon side by side with the 



206 



THE ESSENTIALS OF HEALTH 



sensory fibers in the spinal nerve, at (3). After continu- 
ing the length of the motor fibers, the current finally 
stimulates some of the muscles of the arm and they respond 
by a vigorous contraction. Thus it is seen that the sensory 
and motor fibers are separated into distinct bundles at 
their beginning, and they are also separated at their ter- 
mination, the former in the skin and the latter in the 
muscles ; but they were together in one bundle through 
all the distance between. A reference to Fig. 88 may aid 
in making the subject more clear. The nerve current 
travels in the direction of the arrowheads. 

Importance of Reflex Action. — The daily work of the 
body is carried on largely as a result of reflex action. 

The flow of saliva produced 
by mastication is a result of 
reflex action; we could not 
check the flow if we desired. 
The flow of the gastric juice, 
from the stimulus of food in 
the stomach, is purely a re- 

Fig. 88. — A diagram illustrating suit of reflex action. Respi- 
reflex action : S, the skin; M a mus- ^ j g reflex fc due t 
cle. If the skin, S, be touched, the _ _ ' 

nerve current travels in the direction Certain stimuli applied to the 

of the arrows until it stimulates the respiratory center in the me- 

muscle, M, to contract. .. .... „. 

dulla. lhe nervous system 
is constantly performing a vast amount of labor of which 
we are unconscious, and which we are unable to alter, 
except possibly to a limited degree in a few instances. 

Acquired Reflex Action. — Many acts which are at first 
voluntary, and are performed only by a strong effort 
of the will, finally become so natural and easy that they 
are performed unconsciously ; these may be called acquired 
reflex acts. We all have to learn to walk, and it is at first 





Figure A. Figure B. 

PLATE VIII. 



Plate VIII. — Figure A. Illustrating an act of the will. (1), cerebrum, 
(2), cerebellum; (3), medulla; (4, 4), spinal cord; (5), sciatic nerve ; ((>), median 
nerve. The white lines represent that part of the nervous system which is 
involved in the act: the red lines the motor nerves that are called into play: 
and the black lines the sensory nerves. 

The boy desires to balance the book on his thumb. The idea originates in 
his brain : the will stimulates a current in the motor part of the nerves, which 
passes down the brain, medulla, upper part of the spinal cord, and along the 
median nerve. When this nerve current reaches the flexor muscles of the 
arm and hand, it causes these muscles to contract. 

Figure B. —Illustrating rerlex action, during which the brain is not in- 
volved. 

The book accidentally slipped and fell on the toes of the left foot. Instantly 
the foot is withdrawn before the brain even becomes aware that the book 
has fallen. 

The blow of the book stimulated sensory nerves, thereby producing a nerve 
current which extended up the sensory nerve (illustrated by the black line) to 
a point where that nerve enters the spinal cord. The current enters the cord 
through the posterior sensory root, then passes directly across the cord, leaving 
it through the motor root (illustrated by the red line). The nerve current 
then passes down this motor nerve to the flexor muscles of the leg. which eon- 
tract, thereby drawing the foot away from the book. 



THE PHYSIOLOGY OF THE NERVOUS SYSTEM 207 

a very difficult process, accomplished with considerable 

effort. The number of muscles brought into play in run- 
ning and jumping is very great; yet they all relax and 
contract at just the proper time, without the least aid 
from the will. When the beginner plays the piano, he 
not only looks at the music, but also at the keys, that 
only the right ones may be touched ; but after a time the 
sight of a particular note calls forth such a movement of 
the hand that just the proper key is touched. The per- 
former looks at the music, and the hands take care of 
themselves. The first trials at skating are not highly 
successful. All the power of the will has to be exercised 
to keep the balance and to move in the desired direction ; 
but soon the movements become easier and the exercise 
becomes a pleasure and a rest. 

Habit. — A habit is an action acquired by frequent 
repetition. It is a law in physiology that each time a 
nerve cell acts in a particular way, it gains a power that 
makes the second act more easily performed. In this way 
a habit is formed : it may be the habit of walking, of skat- 
ing, or of playing the piano ; it matters not what the acts 
are, provided the nerve centers become accustomed to 
their repetition. An effort of the will is necessary to 
form a habit ; but, once formed, it takes another effort 
of the will to break it. 



CHAPTER XXIII 

THE HYGIENE OF THE NERVOUS SYSTEM 

Necessity of a Healthy Nervous System. — Since all the 
functions of the body are dependent upon the activity of 
the nerve centers, it is easy to understand that these 
must be in the best condition, or the parts under their con- 
trol will suffer. 

Heredity. — When Ave recognize how strikingly children 
often resemble their parents in appearance and in disposi- 
tion, it will not seem strange to us that scientists trace 
a still closer connection. They tell us that children of 
parents who are robust and vigorous, with sound nervous 
systems, under good control, are more likely to be free 
from physical and moral ills than are the children of those 
parents who have weakened their bodies, and particularly 
their nervous systems, by excess of any sort. This means 
that people ought to regard all the laws of health, and ought 
to follow the highest and best method of living, — for the 
sake of their children as well as for the effect on them- 
selves. It does not mean, however, that the child who 
has- weak or vicious parents must necessarily follow in 
their footsteps. Surely no boy would feel that because 
his father had a very bad temper he also must give way 
to anger and to ill feeling. He might be tempted to do 
so more frequently than the boy whose father or mother 
had a nervous system that was under better control ; but 
he could conquer that tendency. When such a boy masters 

208 



THE HYGIENE OF THE NERVOUS SYSTEM 209 

himself, he comes off a glorious victor. So no one need 
be discouraged if he starts with a physical or a mental 
handicap ; he can triumph in conquering it. 

A Healthy Body. — Even with a vigorous nervous system 
and a strong moral nature transmitted to us, all our bright 
hopes may be easily thwarted by neglecting to obey some 
of the well-known laws of health. To develop the nervous 
system requires proper food, pure air, and plenty of 
mental and physical exercise. Physical weakness is not 
conducive to good brain work ; a tired body will not 
stimulate the brain to action ; hence we conclude again 
that a healthy body is necessary for the highest and best 
development of the whole nervous system. 

Exercise of the Mind. — As muscular exercise is essential 
to the full development of the muscles, so mental exercise 
is necessary if the best efforts of the brain are desired. 
This exercise must be regular, persistent, and properly 
suited to the age and health of the person. It is impossi- 
ble for the boy to jump as far at the first trial as he will 
after weeks of practice ; neither can he perform as severe 
mental work at first, as he will after months of constant 
study. 

If the muscles have not been previously trained, one 
hard effort at lifting or running may cause severe pain and 
soreness in them. So an extra effort of the mind for one 
unaccustomed to study may cause headache and even 
severe mental disorders. The evils of over-study and of 
crowding too many studies into each school year are being 
more fully understood and corrected, while more attention 
is being given to a better understanding of the laws of 
health. The modern teacher knows that a pupil with a 
healthy body is far more likely to have a vigorous mind, 
and that the proper care of each should go hand in hand. 



210 THE ESSENTIALS OF HEALTH 

Mental labor ought not to cease with the school life ; 
the .school is to discipline and train the mind so that the 
powers of observation and reasoning may be used through- 
out life to the best possible advantage. " Work " is an 
important factor in maintaining a healthy body and a 
well-balanced mind, — regular, systematic, persistent work, 
for both the body and the mind. Pleasures are more 
enjoyable, and amusements are more profitable, if we 
make them but the short vacations in our daily duties. 
A life of utter idleness and pleasure seeking is not the 
normal condition of any human being. There should be 
a right proportion of work and pleasure in each day's 
programme. 

Rest. — The mind, as well as the body, would soon fail 
if it were obliged to work too hard or too long. Rest is 
absolutely necessary for all parts of the body. Many 
individuals seem to think that rest means to fold the 
hands and remain in perfect idleness ; as a rule, this is 
the poorest method of obtaining rest. If we have been 
exercising the mind until we are tired from study, nothing 
will restore the mental vigor better than some gentle out- 
door sport, like a brisk walk. The exercise brings a good 
supply of fresh blood to the brain, and thus aids in giving 
new life to its tissue. The headaches of school children 
often cease before they have reached their homes at the 
close of day. 

Some one has said that the only true vacation is a change 
of occupation — and there is a good deal of common sense 
in the saying. Amusements, excursions, and a change in 
the character of the work, all tend to repair the waste of 
nervous energy, and are far better than idleness. Com- 
plete rest and quiet are not conducive to health unless for 
particular reasons they have been ordered by a physician. 



THE HYGIENE OF THE NERVOUS SYSTEM 211 

Worry. — Above all things do not worry. Study hard, 
play hard, enter with enthusiasm into all the duties and 
pleasures of school life, but do not worry. Worry 
means waste — waste of nervous force, of thought, of 
memory ; and it is a sure road to the impairment of the 
highest functions of the brain. While it is true that some 
students do not have interest enough in doing their work, 
yet it is equally true, especially in the higher grades, that 
many attempt to accomplish altogether too much. 

Sleep. — One of the great restorers of both mind and 
body is sleep. All animals having a well-developed ner- 
vous system take rest in sleep. Drowsiness and weariness 
warn us that sleep is necessary. These warnings may be 
unheeded for a time, but sooner or later we have to yield 
to the imperative demand. Some persons require more 
sleep than others, but the adult needs, on the average, 
from seven to nine hours of sleep daily. It is said that 
Napoleon required but three or four hours' sleep each day, 
and that he would pass days with very little rest of any 
kind. Frederick the Great required but little sleep, not 
over five hours a day. These are marked exceptions. 
Nearly all our great men who are obliged to do an immense 
amount of brain work sleep well and long: they know the 
value of a good night's rest, and are alarmed when they 
are unable to procure sleep. They know that during their 
busy days the waste is greater than the repair, and that 
during the quiet rest of the night the cells are busy re- 
pairing the waste, and appropriating new material for the 
labor of another day. 

Insomnia. — Continued wakefulness often becomes a very 
serious trouble, and many men have lost their health by 
the inability to sleep. If the condition is persistent, it is 
best to consult a physician for relief, instead of taking 



212 THE ESSENTIALS OF HEALTH 

sleeping powders or any other quieting drugs on one's 
own responsibility. 

To promote Sleep. — There are many popular ways of 
promoting sleep, nearly all of which make a bad matter 
worse. Out-door exercise during the day, light suppers, 
quiet evenings, and warm feet will greatly promote sleep. 
" Keep the head cool and the feet warm" is an old piece 
of advice worth remembering. To make sure of a good 
night's rest, the tired brain must be free from cares, 
griefs, and anxieties. Infants always require food before 
they are put to bed for the night, and young children may 
need a cracker, or some other light food. 

We must remember that the brain works, and hence 
wears out like any other tissue ; it must therefore be kept 
well supplied with new material. School children need 
plenty of plain, wholesome food, and an abundant supply 
of fresh air. 

Students need much Sleep. — Students often make a great 
mistake in trying to change the laws of nature, by study- 
ing until late into the night, and then in sleeping away 
the morning hours. The sleeping room should be quiet, 
darkened, and supplied with cool, fresh air. At night the 
brain is tired, and an extra effort is necessary to make an 
impression upon it ; in the morning it is fresh and sensitive 
and easily impressed, which proves that the morning is 
the better time for study. Earnest application in the 
early part of the day, concentrating the mind with all the 
power of the will, and laying aside everything else but 
the work in hand, — this will accomplish the best results 
from study, and leave the evenings for relaxation, and the 
nights for sleep. 

Effects of Alcoholic Drinks upon the Nervous System. — 
When cells of different composition are brought into con- 



THE HYGIENE OF THE NBBVOUB SYSTEM 'IVi 

tact with alcohol, it has been found that those most deli- 
cate in structure are the soonest affected. The cells of the 
nervous system are the most delicate of any in the body, 
and thus it is the nervous system that first shows the 
effects of alcohol, when any drink containing it has been 
taken into the body. 

The first noticeable effect of alcohol upon the drinker is 
usually a flushing of the skin from the expansion of the 
small blood vessels. Quickly afterward follows a kind of 
mental excitement that has often been misinterpreted as 
an increase of mental power. The real nature of this 
effect of alcohol was not understood until it began to be 
studied by scientific investigation with exact methods and 
trained observation. Then it was found that the so-called 
exhilarating effect of a glass of wine or beer is an abnormal, 
unhealthful state, caused by the poisonous effect of the 
drug. After such a drink, a person cannot add a column 
of figures so correctly as before, he cannot commit to 
memory so well, he cannot give such close attention to 
any subject ; his powers of observation and perception 
are weakened, — he thinks on a lower level. 

In a healthy condition, the mind gains speed and skill 
by practice. Alcohol neutralizes the benefit of practice 
by reducing the mental operations to the untrained state 
preceding practice. Similarly, education, training, cul- 
ture, refine the mind and increase it powers, enabling it to 
think upon larger subjects, to discriminate more closely, 
to see finer shades of meaning, to pay more attention to 
propriety of conduct. Alcohol wipes out these advan- 
tages, reducing the cultivated mind to the level of the 
uncultivated. 

One of the most serious effects of alcohol upon the mind 
is its weakening of the power of self-control. Nothing is 



214 THE ESSENTIALS OF HEALTH 

more unfounded than the scorn one sometimes hears 
expressed of the person who, it is said, " does not know 
when he gets enough. " Such a remark betrays ignorance 
of the power of alcohol to destroy self-control by weaken- 
ing first of all that part of the body which alone can ex- 
ercise self-control, the brain. The time for self-control is 
before the brain is injured, by refusing to take a drink of 
brain poison. As well expect a person to remain awake 
after taking a fatal dose of opium, as to expect a full 
measure of self-control from a man after he has taken a 
drink of any alcoholic liquor. 

The foregoing applies to the effects of small doses of 
alcohol. The effects of the continued or habitual use of 
either large or small quantities is a gradual impairment 
of the brain and consequent weakening of all its functions. 
A series of experiments performed in Germany a short 
time ago proved that the effects of a single dose of alco- 
holic drink taken in the evening lowered the working 
ability the following day, and, if the dose was large, the 
second day also showed some bad results. 1 If the practice 
was continued for several nights, the working ability 
steadily declined for several days after the alcohol was 
stopped. Even then there was not complete recovery, for 
upon resuming the alcohol again the effects were worse 
than the first time the experiment was tried. 

The fact thus established, that alcohol taken at night 
reduces working ability the following day, shows the mis- 
take made by those who think they can take wine or beer 
or some other alcoholic drink with the last meal of the 
day, after their day's work is done, without being harmed 
by it. They are sowing the seeds of failure in their health 
and in their business, and the crop may mature in both. 

1 Krsepelin — Wiener Klinischer Wochenschrift, October 17, 1899. 



THE llYaiENE OF THE NERVOUS SYSTEM 215 

The last stages of the effect of alcohol upon the nervous 
system are seen in the mental and moral wreck whose last 
hope is the inebriate asylum. He lies ruined and helpless 
at the bottom of an inclined plane whose top was his first 
glass. 

In Germany, in the universities and other centers of learn- 
ing where these important truths concerning the effect of 
alcohol have been tested and proved, students are banding 
together in abstinence societies to oppose the drinking 
customs that have so long prevailed there. The absurd 
treating and toasting customs of our country call for an 
equally courageous stand by every student who learns that 
it is the nature of alcohol to weaken the brain, enslave 
the appetite, and block the development of one's best and 
highest possibilities. 

It is now a well-established fact that the disastrous 
effects of alcoholic drinks can extend farther than the 
drinker. It can make his children weaklings or defec- 
tives. Some one has said that every child has the right of 
being well born. The drinker should remember that by 
taking alcoholic drinks he is depriving his children of that 
birthright. Children who have the misfortune to inherit 
some of the evil consequences of parental drinking need 
particularly to avoid all use of alcohol and other narcotics, 
and to live as healthfully as possible in all other respects, 
in order to overcome the hereditary weakness. 

Dr. A. H. Stehr, a German physician , in a recent work on 
the use of alcohol and academic work, says : " The injury to the 
working ability of the muscles is small compared to the injury 
to the brain, which is the chief organ of academic activity. 
The work of the student certainly places the highest strain 
upon his mental functions, because he is not following beaten 
paths but has to open new ones. He must be able to judge 



216 THE ESSENTIALS OF HEALTH 

causes and consequences, to verify unfamiliar mental pro- 
ductions, to trace clearly coordinate, subordinate, and causal 
relations. Later he will become one of the class from whom 
almost alone comes the creative work and thereby the condition 
of the progress of civilization in his country. The student 
from his boyhood must be free from the constraint to drink, ' 
which is a yoke upon so many German students. The drink- 
ing customs must be abolished by the knowledge that alcohol 
hangs like an iron weight upon all higher mental activity. 
Artistic ability is an activity of the imagination and intuition 
which, as Helmholtz's well-known remark puts it, is banished 
by the smallest amount of alcohol, while numerous poets and 
artists have emphasized the injurious effects of alcohol upon 
their productions." 

Prof. J. J. Abel, of Johns Hopkins University, says, " Every 
man who, according to his own notions, is only a moderate 
drinker places himself by this indulgence on a lower intellectual 
level and opposes the complete and full utilization of his intel- 
lectual powers." 

The Journal of the American Medical Association, 1902, 
said, " There is good testimony, not yet controverted, or even 
contradicted, that comparatively small doses of alcohol have 
a direct deleterious action on the nervous functions and the 
capacity for work." 



CHAPTER XXIV 




THE SENSE OF SIGHT 

Protection for the Eyes. — The eyes are well protected 
in deep sockets of bone, called the orbits. Externally 
they are protected by 
the eyebrows, the eye- 
lids with their glands, 
the eyelashes, and the 
lachrymal glands. The 
nose is also a valuable 
protection (Fig. 89). 

The Eyebrows. — The 
eyebrows project over 
the eyes and are covered 
with a thick growth 
of hair. The hair is 
directed obliquely out- 
ward, so that the per- 
spiration from the fore- 
head is carried to the 
side of the face, instead of running directly down into 
the eyes. 

The Eyelids. — The eyelids are curtains placed directly 
in front of the eyeballs. In the center of each eyelid 
is a thin plate of cartilage, on "the outside of which is a 
thin muscle covered with skin. The inside of the lids 
is lined with a delicate membrane, called the conjunctiva. 

217 



Fig. 89. — The muscles of the right eye- 
ball. The outer bony walls of the orbit have 
been removed. (1) The muscle which turns 
the eyeball upward; (2) downward ; (3) out- 
ward ; a corresponding muscle on the inner 
side moves the eyeball inward; (4, 5) mus- 
cles which rotate the eyeball : (6) a pulley, 
through which the tendon of the muscle (5) 
moves. 




218 THE ESSENTIALS OF HEALTH . 

On the edges of the lids is a row of delicate hairs, 
called eyelashes. They protect the eyes from insects 
and particles of foreign matter ; for the moment any for- 
eign bodies come in contact with 
the lashes the lids close, thus pre- 
venting the objects from touching 
the eyeball. The eyelids keep 
the heat and cold from the more 
delicate parts of the eye, and 
they also keep out an excess 
of light. Their most important 
function is to cleanse the eyes 

Fig. 90. — The eyelids of the J 

right eye, viewed from the in- and to keep them moist. Their 
side: (l) the lachrymal gland ; ra pid and frequent movements 

(2) the oil glands in the eyelids. . -, -, -, . . t 

thoroughly remove any particles 
of dust from the front of the eyeball, while at the same 
time they moisten the surface. This is the object of 
winking, which is usually a reflex act, although it may 
be made voluntary. 

The Oil Glands. — Oil glands are situated at right angles 
to the free edges of the lids, and on their inner side. 
They can be seen on the inner surface of the eyelids 
through the mucous membrane, looking like strings of 
minute pearls. They extend nearly across the entire 
width of the lids, on the edges of which they open and 
pour out their oily secretion. This keeps the lids from 
adhering to each other, and holds back the tears so 
that they do not under normal conditions run over the 
edges and down upon the face. 

The Lachrymal Gland. — The lachrymal gland is an 
almond-shaped body placed in the outer and upper part 
of each orbit, between the eyeball and the bone. From 
this gland there extend about seven ducts or canals, which 



THE SENSE OF SIGHT 



219 



open on the inner surface of the upper eyelid near its 
outer part. The openings are arranged in a row, as repre- 
sented at (2), Fig. 90, thus distributing the secretion over 
the surface of the conjunctiva. 

The Tears. — The watery secretion from the lachrymal 
glands is known as the lachrymal fluid. The secretion is 
a constant one, although 
we are unconscious of 
its presence until there 
is an excessive flow; the 
fluid is evenly distrib- 
uted by the movements 
of the eyelids. An ex- 
cessive amount of this 
secretion is called the 
tears. They are easily 
excited by irritants af- 
fecting the eye or nose ; 

° j • FlG * 91. — Front view of the right eye, 

by laughing and Crying, showing the location of the lachrymal gland 

and the nasal duct : (1) the lachrymal gland ; 

(2) the ducts that carry the secretion from 
the gland to the free surface of the eyeball ; 

(3) the duct for the passage of the secretion 
to the nose ; (4) the iris, in the center of 
which is the pupil. 




mental 



and by various 
emotions. 

Some of the secretion 
is evaporated from the 
eyeball, but the greater 
part of it escapes from the eye through regular channels 
provided for it. The secretion flows toward the inner 
angle of the eye, where it enters two openings, one in each 
lid. On the lower lid this opening is easily seen as a dark 
point in the center of a little eminence near the inner 
corner of the eye. These points, which look dark as all 
small openings do, are the beginnings of two ducts which 
pass inward toward the nose, as will be seen at (3), 
Fig. 91. 



220 THE ESSENTIALS OF HEALTH 

The Eyeball. — The eyeball is securely protected from 
injury and yet it has a most extensive range of vision. 
It is a round body, with the exception that its front part 
protrudes; and is about an inch in depth (Fig. 92). 

The eyeball has three membranes or coats surrounding 
it. (1) The outer coat consists of two parts ; the trans- 
parent cornea, through which the light passes into the eye, 

and the hard, thick part tying 
just behind it, commonly 
called " the white of the 
eye." Its scientific name is 
the sclerotic. 

(2) The middle coat of 
the eye is called the choroid ; 
it is filled with dark pigment 
which makes it look quite 
black. The choroid joins a 
fig. 92. -a section through the membrane in front, called the 

eyeball: (1) the cornea, or the trans- iris, in the Center of which 

parent membrane which forms the • • -n 1 ±1 

front of the eye; (2) the sclerotic; 1S ai1 opening, called the 

(3) the choroid ; (4) the retina ; (5) the pUpil. In the iris are the 

optic nerve ; (6) the blind spot; (7) the ce i ls? containing a coloring 

iris ; (8) the lens ; (9) the aqueous , . , 7 . , , 

humor; (10) the vitreous humor. matter, which give the char- 
acteristic color to the eye. 
The size of the pupil can be changed by the action of 
certain muscles : the muscles are involuntary so that 
they contract and relax only as a result of some influence 
outside of the will. A bright light will make the 
muscles of the iris contract so that the pupil becomes 
much smaller, and thus but little light reaches the interior 
of the eye. If the light be very faint, other muscles of 
the iris contract, enlarging the pupil, and thus allowing 
more light to enter. 




THE SENSE OF SIGHT 221 

(3) The third or inner coat of the eye is called the retina. 
The microscope shows that it has a most complicated 
structure, and that it is directly connected with the fibers 
of the optic nerve, which go directly to the brain. When 
light reaches the interior of the eye, it produces a peculiar 
impression on the retina ; and by some means not known 
to science the brain receives the sensation of vision, or as 
we ordinarily say, we are able to see. When any object 
is viewed^ the exact image of it is produced on the retina. 
If the optic nerve be cut, the image will still be formed, 
but no sensation of light will reach the brain. Just as in 
photography, it is the photographer who sees and not his 
camera, so it is the brain which sees and not the eye, for 
the eye corresponds to the camera. 

Functions of Parts. — The eyeballs may be likened to a 
room, with a single window in front. Just back of the 
window hangs a dark curtain with a round opening in it. 
All light entering the room must come through the win- 
dow, pass through the opening in the curtain, and strike 
the opposite wall. The transparent cornea is the window ; 
the iris is the dark curtain for regulating the amount of 
light ; the pupil is the central opening ; and it is the 
retina that receives the impression of light. The choroid 
(the middle coat) is black to prevent the reflection of light 
within the eye, and to absorb any light which may pass 
through the retina. The sclerotic is hard and firm, for a 
protection to the eye and for the attachment of muscles. 

The Blind Spot. — All parts of the retina are not equally 
sensitive to light. One spot on it, where the optic nerve 
enters (see Fig. 92, 6), is entirely insensible to light. 
This is called the blind spot : it does not interfere with 
vision, because it is impossible for the light from an object 
to fall on the blind spot of both eyes at once. If certain 



222 THE ESSENTIALS OF HEALTH 

rays fall on the blind spot in the retina of one eye, they 
will fall on a different part of the retina of the other eye. 
But if one eye be closed, there is always some portion of the 
object before us which is invisible. This is easily proved 
by looking at a sharply defined object after the following 
manner : close the left eye and look steadily at the small 
white circle to the left of Fig. 93: it is possible now to 
see the large white circle even when the eye is fixed on 
the smaller one. Hold the book vertically on a level with 
the eyes at a convenient distance. Now move the book 
slowly backward and forward. Soon a distance will be 




Fig. 93. — A diagram for illustrating the existence of the blind spot. 

found where the large circle entirely disappears, only to 
reappear again as the book is moved nearer or farther 
from the eye. This is because the light from the large 
circle, when it entered the eye at a certain angle, fell on 
the retina just where the optic nerve enters. 

Color Blindness. — Color blindness may be total or par- 
tial. When total, all objects appear gray. These cases 
are very rare. The usual cases of color blindness are 
those where the persons cannot distinguish between red 
and green. This is a serious defect, especially if occur- 
ring in engineers, who depend upon the green and red 
light signals at depots, railroad yards, etc. 

Shortsightedness; Farsightedness. — In a normal eye, 
an image of all objects seen distinctly is formed on the 



THE SEXSE OF 81GHT 



223 



retina. If the eye is too deep, that is, if its diameter 
from before, backward, is too great, then the image is 
formed in front of the retina and appears blurred. If 
the object be held very near the eye, however, the image 
is formed on the retina and vision A 

is distinct. As the field of dis- 
tinct vision is thus limited to 
near objects, the defect is called 
near or shortsightedness. It is 
remedied by wearing concave 
glasses. In farsightedness, either 
the eye is not deep enough, or 
the lens may not be of the proper 
curve. This is quite a common 
defect after forty or fifty years 
of age. It is remedied by wear- 
ing convex glasses. 

Care of the Eyes. — The eyes 
may look bright and clear, yet if 
their use in reading is followed 
by pain in the head, it is probable 
that there is some defect in vision. 
A clear and steady light is most 

. J , . Fig. 94.— Diagrams illustrat- 

desirable ; a dim light makes it ing the path of the light rays 

necessary to put forth an effort entering A, a normal eye, B, a 

to see, While a Strong light is ^sighted eye and C, a short- 

° ° sighted eye. Notice how in the 

equally harmful. Looking at the normal eye, A, the light focusses 

sun or any other brilliant light is on the retina > and so the ima ^ e 

....... ,-,, , . , , resulting is a true image. 

positively injurious. The light 

should come from over the left shoulder, so that it may 
fall on the page of the book without coming directly into 
the face. Squinting, or looking cross-eyed, or rolling the 
eyes about, as is often done by children in sport, is a 




224 THE ESSENTIALS OF HEALTH 

dangerous thing, as some of the muscles of the eyeball 
may be severely strained by so doing. 

To read while lying down, especially in bed, is a very 
unwise practice, as the eyes cannot focus .naturally for 
reading when the body is in this position. The upright 
position is the natural and proper one for reading. The 
book should be held at twelve to sixteen inches from 
the face. Students are advised to notice their usual 
manner of reading and studying, at their desks and in 
their own homes. Many will find that they are forming 
habits which ought to be corrected. Those who cannot 
see ordinary type, unless the book is nearer than ten inches, 
should consult an oculist and ascertain whether it would 
not be better to wear glasses. Never rub the eyes, for 
any reason, especially if some particle of dirt has fallen 
into them ; have all such objects carefully removed at once 
by some competent person. 

Eye Strain. — When the image of an object is not 
formed distinctly on the retina, as in shortsightedness or 
farsightedness, the cause is usually a defect in the shape 
of the eyeball, which is roughly illustrated in Fig. 94. 
In such cases the image does not focus on the retina, 
as it should, see B and C, and the muscles of the eye 
make a constant effort to bring the focus right. This 
results in straining the muscles, thereby causing pain in 
the eyes, headaches, sick headaches, and other affections 
of a more serious character. Constant headaches should 
always send one to consult an oculist or a physician, to 
see if glasses are necessary. 

Relation of Attention to Mental Growth. — We should 
not only take the best of care of our eyes, but we should 
also train them in order that they may serve us better. 
This may be done by cultivation of the power of atten- 



THE SENSE OF SIGHT 225 

tion, learning to notice objects about us quickly and 
accurately. Take a stroll through the woods or over the 
fields, count the different kinds of birds, note the move- 
ments of the squirrels, look at the flowers, the rocks, the 
brooks, and thus begin to learn how valuable the eyes are, 
when rightly directed, to the proper growth and develop- 
ment of the mind. In this way also we come near to 
Nature and learn better how to love all her wonderful 
works. Habits of quick observation and accurate de- 
scription, formed thus early in life, w^ill prove of great 
value in after years. 

Injurious Effects of Alcohol and Tobacco. — Long-con- 
tinued and frequent indulgence in alcoholic liquors may 
have a very serious effect upon the eyesight, resulting in 
degeneration of the optic nerve. 

Several cases of degeneration of the optic nerve, 
from the use of cheap flavoring extracts put up with 
methyl or wood alcohol, have recently been reported. 
Some authorities have held that common or ethyl alcohol 
did not produce this disease, but a series of very careful 
microscopic examinations made a few years ago proved 
that in cases of chronic poisoning with ethyl alcohol, the 
same degeneration of the optic nerve resulted. 1 

Tobacco is a well-recognized cause of this disease. The 
edges of a smoker's eyelids are often inflamed as a result 
of contact with the irritating smoke. Frequently the 
smoker experiences sharp pains in the eyeballs, w T ith more 
or less failure of vision. 

One of the most serious results to the eyes from the use 
of tobacco is known as " smokers' blindness." 

1 Friendenwald — Johns Hopkins Hospital Bulletin, 1902. 



CHAPTER XXV 



THE SENSES OF TASTE AND SMELL 



The Tongue. — The sense of taste is located in the 
tongue, in the back part of the roof of the mouth, and, to 

a slight extent, in the sides 
of the throat. The mucous 
membrane covering the upper 
surface of the tongue, how- 
ever, is more especially the 
seat of this sense. The tongue 
is composed of voluntary mus- 
cle, covered with mucous 
membrane. In health, it is 
moist and of a light red color. 
Any marked change from this 
condition is an indication of 
some departure from health. 
Thus the appearance of the 
tongue often gives aid to 
the physician in ascertain- 
Fig. 95.— The tongue, showing the ing the source and character 

varieties of papillae. f t h e disease. 

Papillae of the Tongue. — The mucous membrane of the 
tongue is covered with a great number of papillae (Fig. 
95). There are three varieties on the surface of the tongue. 
The largest papillae can be seen by the unaided eye ; they 
are far back at the base of the tongue, arranged in the 

226 




THE SENSES OF TASTE AND SMELL 



227 



form of the letter V, with the point of the V toward the 
back. There are eight or ten of these, each consisting of 
a central papilla surrounded by a wall. The second vari- 
ety can also be seen with the unaided eye, and they are 
easily recognized by their deep red color. They are most 
abundant at the tip of the tongue, where they present a 
club-shaped appearance. The third variety is the most 
numerous of all. These papillse are minute in size, 
conical in shape, and cover the front two-thirds of the 
tongue. They are of a whitish color, owing to their 
thick epithelial covering. 

In some of the papillse are found loops, or coils, of 
minute blood vessels ; in others there is the ending of a 
nerve fiber, giving the sense of touch to the tongue ; 
while in other papillse are minute bodies, the taste buds, 
especially for the sense of taste. 

The Taste Buds. — The taste buds are found in the large 
papillse at the base of the tongue ; and a few are also 
distributed to other 
papillse. They are col- 
lections of cells ar- 
ranged in the form of 
buds, hence called taste 
buds. Each bud is not 
over 3^- of an inch in 
length. The location 
of these bodies, in the 
edges of the papillse, is 
illustrated in Fig. 96. It is seen that they are situated in 
the folds between the papillse, rather than on the upper 
free surface. Some of the cells composing each bud 
are directly connected with a nerve fiber, so that when- 
ever anything comes in contact with these cells, an im- 




Fig. 96. — A section through two papillse 
of the tongue, showing the taste buds A, 
magnified. 



228 THE ESSENTIALS OF HEALTH 

pression of its " taste " is conveyed down the cells and 
along the nerve fibers to the brain. 

The Sense of Taste. — There are four different qualities 
of taste. We have the sensations which we distinguish 
as sweet, bitter, acid, and salt. In order that any of these 
may be recognized, the substance must be dissolved. Dry 
sugar placed on a perfectly dry tongue produces no 
sensation of sweetness. Some of it must be dissolved 
before any effect is produced on the cells of the taste 
buds. The saliva aids in this, and there are also mucous 
and serous glands in the tongue which secrete a watery 
fluid. The movements of the tongue promote the flow 
of these secretions, and thus aid in dissolving the sub- 
stances and in distributing them over a greater surface. 
The sense of taste can be greatly improved by practice; 
it is materially aided by the sense of smell. 

Confusion of Taste and Smell. — The senses of smell and 
taste are often confused. Many times we believe we taste 
a substance, w r hen it is only the odor which is perceived. 
It is stated that neither vanilla nor garlic has any distinct 
taste ; it is their odor alone which is noticed. The odor 
of a drug is often more disagreeable than its taste ; for this 
reason many medicines are best taken after first closing 
the nose and thus avoiding the odor. A severe cold is 
said to affect the sense of taste ; this is largely because the 
lining membrane of the nose is inflamed, and we are unable 
to distinguish odors. In man the sense of taste is more 
highly developed than that of smell, while in some of the 
lower animals, the dog for instance, the sense of smell is 
the more acute. 

Habit in choosing Food. — The taste of many substances 
which were at first very pleasant may become disagree- 
able because of too frequent use, or of unpleasant associa- 



THE SENSES OF TASTE AND SMELL 229 

tions; some articles of food are distasteful when first 
used, but after a time they are greatly desired. Many 
persons have had to make repeated trials before becoming 
fond of oysters, tomatoes, or olives ; they began by taking 
small quantities, gradually educating their sense of taste, 
until a fondness for these foods was acquired. Habit has 
much to do with this, for we often like and dislike those 
things which we are in the habit of seeing other members 
of the family like and dislike. 

Impressions of Taste Remain. — If a very sweet or a 
very bitter substance be placed in the mouth and then 
removed, the taste is retained for some time. Therefore, 
if one substance be tasted and then quickly followed by 
others of different tastes, the impressions will be confused. 
If the taste of the first was well marked, it may impart 
its qualities to those following. Therefore, to take a 
medicine which has a disagreeable odor and taste, first 
hold in the mouth some strongly flavored substance ; then 
close the nostrils to avoid the odor, and swallow the medi- 
cine. In this manner, for reasons already given, there 
will be little taste of the drug itself. Young persons 
often form the habit of eating cloves and other spices : 
this is very harmful, not only because " it is likely to 
injure the sense of taste, but also because it in many 
cases results in a serious disturbance of the action of the 
stomach. 

Tobacco and Taste. — Tobacco blunts the sense of 
taste. This is exactly what we should expect; for the 
papillse of the tongue become saturated with the tobacco 
flavor, and the taste buds are impaired by their contact 
with the poisonous properties of the nicotine. The taste 
of tobacco is continuously in the mouth, preventing other 
substances from being tasted unless they are highly 



230 



THE ESSENTIALS OF HEALTH 



spiced ; this leads to disorders of the stomach as already 

described. 

The Nose. — The sense of smell is located in the nose. 

The two openings into the nose are called the nostrils. 

At the front they are lined with a number of fine 

hairs, which aid in keeping foreign bodies from enter- 
ing the nasal cavities. 
The framework of the 
nose consists of bone 
and cartilage. A thin 
wall, called the septum, 
divides the interior into 
two cavities ; these are 
irregular in shape and 
extend from the nos- 
trils, in front, to the 
upper part of the phar- 




ynx, behind. The in- 



Fig. 97. — The outside of the right nasal cav- 
ity, showing the three turbinated bones. 

side ot each, or the side 
toward the median line, is smooth, because the septum 
itself is smooth ; but the outside is most irregular, owing 
to the presence of three curved or scroll-like bones, called 
the turbinated bones. These are well shown, as viewed 
from the side, in Fig. 97. Lining each nasal cavity is 
a mucous membrane, which is especially thick over the 
turbinated bones (Fig. 98). 

The origin of the odors which we perceive in objects is 
a very obscure matter, — scientists have several theories 
about it, but none are fully proved. We know, however, 
that most substances, probably all substances, have the 
property which we call odor and that under certain 
circumstances we perceive it. 

Conditions affecting this Sense. — In order to appre- 



THE SENSES OF TASTE AND SMELL 



231 




ciate the odor of a substance, it must be brought to the 
olfactory nerve (consult Fig. 99) as a gas or vapor. Solid 
or liquid bodies, in the nose, do 
not produce any sense of smell. 
This is easily proved by rilling the 
nose with rose water ; after so 
doing, no odor is perceived from 
the rose water. 

The continued influence of an 
odor blunts the acuteness of smell. 
This is illustrated in everyday life. 
Upon first entering a room, we 
may notice the odor of escaping 
gas, while in a short time we be- 
come unconscious of its presence. 
We notice that a room is " close " 
only when we first enter it. In all 
such cases the first impressions 
should be the guide. Some per- 
sons are extremely susceptible to odors of all kinds ; they 
not only quickly detect the unpleasant odors, but they are 
often made ill by them. In some people the inhalation 
of certain powders excites violent inflammation of the 
nasal passages. 

The sense of smell may be greatly developed. It is 
related of a certain boy named James Mitchell, who was 
born deaf, dumb, and blind, that he could accurately 
identify many objects, simply by the sense of smell. 

Use of Sense of Smell. — The sense of smell is of use 
in many ways. It aids in the choice of foods, for, as a 
rule, food that has a tainted odor is unfit for use ; and it 
aids in the detection of impurities in the air. This sense 
is set on guard over the place where air enters the body, to 



Fig. 98. —Transverse sec- 
tion of the framework of the 
nose; (1) the nasal cavities. 
On the outside of each cavity 
are the curved turbinated 
bones ; (2) the bones forming 
the roof of the mouth and the 
floor of the nasal cavities. 
The black represents the 
bone, the lighter shade rep- 
resents the mucous mem- 
brane covering the bone. 



232 



THE ESSENTIALS OF HEALTH 



give warning of approaching danger. It is true that this 
sense does not warn us of the injurious agents in the air 
which cause the contagious diseases, yet it does give 
notice of offensive vapors which are dangerous to inhale. 

Vapors which are irritating 
to the nose would be much 
more so to the more delicate 
tissues of the lungs. It is 
^ safe to say that in the ma- 
jority of cases, disagreeable 




odors mean dangerous odors. 
Sense of Smell in Animals. 
— In some of the lower ani- 
mals, the sense of smell is 
developed to a marvelous 
degree. The capabilities of 
the dog are none the less 
wonderful because so com- 
monly observed. We all 
know how he will return 
home after having been taken 
away long distances ; how he will track his master through 
crowded streets and in crowded halls ; how he will recog- 
nize clothing ; and how he will follow the trail of the fox 
for many miles. Other animals, as for example the lion, 
can tell of the approach of man, or of the nearness of 
prey; while the deer can detect "in the air" the approach 
of an enemy when a great distance away. 



Fig. 99. — The right nasal cavity, 
showing the termination of the olfac- 
tory nerve : T, the turbinated bones, 
as represented in Fig. 97; O, the 
olfactory bulb, lying beneath the front 
part of the cerebrum, C ; B, the bony 
floor on which rests the cerebrum. 



CHAPTER XXVI 



THE SENSE OF HEARING 




The Organ of Hearing. — The organ of hearing consists 
of three parts : the external ear, the middle ear, and the 
internal ear. The vibrations of the air are collected by 
the external ear, received 
by the middle ear, and 
transmitted through its 
bones to the inner ear. 
The inner ear contains 
the termination of the 
nerve of hearing, or the 
auditory nerve. 

The External Ear. — 
The external ear consists 

Fig. 100.— The ear: C, the auditory canal, 

Of a framework of Carti- that leads to the middle ear; D, the tym- 

lage which is looselv P an * c membrane at the inner end of the 

, -. , , canal; M, the middle ear, or drum, in which 

attached to the bones are three minute bones; I, the inner ear; 

of the head and to the IS", the auditory nerve going to the brain ; 

auditory Canal. The ex- T > *J. e Eusta ^ tube, leading from the 
J middle ear to the upper part of the pharynx, 

ternal ear can be slightly 

moved by the action of certain muscles, although in man 

this is barely perceptible. In the lower animals, the 

movements are very extensive, and the ear is quickly 

changed from one position to another to catch better the 

sound coming from any quarter. 

The auditory canal is about an inch or an inch and a 

233 



234 



THE ESSENTIALS OF HEALTH 



quarter in length, and extends from the external opening 
to the middle ear. Near the orifice are a number of fine 
hairs, and farther in are the openings of glands which 
secrete the earwax. Both the hairs and wax are for the 
protection of the ear, keeping out small insects, dust, and 
other foreign bodies. 

The Middle Ear. — The middle ear, or tympanum, is an 
irregular shaped cavity about one half an inch in length, 
and one fourth of an inch from side to side. It is called 

" the drum of the ear," 
because it contains air 
and has a thin mem- 
brane over one part of it 
which is easily affected 
by wave sounds. The 
middle ear, or the drum, 
is separated from the 
auditory canal by a 
thin membrane, called 
the tympanic membrane ; 
this is often called the 
" drum," but incorrectly so, as it is only the thin mem- 
brane over the head of the drum ; it is elastic, and so thin 
that it is nearly transparent. A study of Fig. 100 will aid 
in locating the parts already mentioned. The external ear 
with the auditory canal, C, is very evident. The middle 
ear, M, is separated from the outer ear by the tympanic 
membrane, represented at D. Directly below the letter M 
are three minute bones, see Fig. 101. A tube extends 
from the middle ear to the throat. At the right of the 
middle ear is the inner ear, at I ; it is most complicated 
in its structure, and is separated from the middle ear by 
a thin membrane against which the stirrup bone rests. 




Fig. 101. — The three bones of the middle 
ear, magnified : H, the hammer, or malleus ; 
A, the anvil, or incus; S, the stirrup, or 
stapes. 



THE SENSE OF HEARING 



235 



The tympanic membrane is often diseased from inflam- 
mation of the middle ear. Not infrequently it has minute 
openings through it, while sometimes it is nearly all 
destroyed. It is the function of the tympanic mem- 
brane to catch the sounds entering the external ear. 
As they strike the membrane, they cause it to vibrate, 
and these excite a corresponding vibration in the parts 
beyond. 

Bones of the Middle Ear. — In the middle ear are three 
bones, so minute that all together they weigh but a few 
grains. Yet they 
give attachment 
to minute mus- 
cles, have mov- 
able joints, and 
perform most im- 
portant work. 
From their pecul- 
iar shapes they 
are called the mal- 
leus, or hammer ; 
the incus, or 
anvil ; and the 
stapes, or stirrup. 
The tympanic 
membrane is at- 
tached to the handle of the hammer ; the hammer, to the 
anvil ; and the anvil, to the stirrup ; thus a chain of 
bones is established from the tympanic membrane across 
the cavity of the middle ear. The outer end of this bony 
chain is attached to a membrane, and so is the inner end. 
Beneath the inner membrane, just opposite the stirrup, in 
the inner ear, is a fluid. Therefore the vibrations of the 




Fig. 102. — The middle and inner ears, from a dif- 
ferent view and on a larger scale than Fig. 100. 
C, the auditory canal of the outer ear ; D, the tym- 
panic membrane ; M, the middle ear ; T, the Eusta- 
chian tube ; I, the inner ear, surrounded by bone; 
S, the stapes; A, the incus; H, the malleus. 



236 THE ESSENTIALS OF HEALTH 

air at last come to affect this fluid in the inner ear. A 
reference to Fig. 102 will make this clear: the sound enters 
the external ear and passes down the auditory canal, C, 
and strikes against the tympanic membrane, D, throwing 
it into vibrations; these vibrations are communicated to 
the handle of the hammer, H ; thence to the anvil, A ; 
thence to the stirrup, S ; and thence to the membrane 
to which the stirrup is attached. As this membrane 
vibrates, it throws the fluid beyond it into correspond- 
ing vibrations; and these so affect the endings of the 
auditory nerve that we have at last the sensation of 
hearing. 

The Eustachian Tube. — The middle ear is not a closed 
cavity. \t communicates with the pharynx by means of 
a passage, called the Eustachian tube. The tube and 
the middle ear are lined with a mucous membrane, and the 
former opens into the upper side of the pharynx directly 
behind the opening of the lower part of the nasal cavity. 
The object of this tube is to equalize the pressure of the 
air on each side of the drum membrane. In the healthy 
ear, therefore, the air in the external ear and that in the 
middle ear are of the same density, with only a thin 
vibrating membrane between. 

The Eustachian tube is ordinarily closed, opening only 
during the act of swallowing, and thus allowing the 
passage of air to the middle ear. As a result of chronic 
catarrhal affections the tube may not open at all for the 
passage of air through it. This condition is one of the 
causes of deafness ; but it is often possible to relieve 
such cases by the use of instruments with which air may 
be forced through the tube into the middle ear. 

The Internal Ear. — The internal ear is the most essen- 
tial part of the organ of hearing, for it contains the 



THE SENSE OF II EARING 237 

terminal fibers of the auditory nerve. Its parts are 
deeply seated in the bones of the skull and are most 
intricate and complicated in structure. 

The Sense of Equilibrium. — A certain portion of the 
internal ear consists of three bony tubes, called the semi- 
circular canals. When these canals are injured in the 
lower animals, it is found that the animal rolls its head 
from side to side, up and down, apparently unable to 
direct its movements. A bird thus injured will experi- 
ence great difficulty in walking to the food placed near, 
and in picking it up. The animal sees well and appears to 
hear well, but it reels and falls, acting as if it were dizzy. 
From these observations and from others made on man, it 
is believed that the semicircular canals contain nerves 
which enable the body to maintain its proper poise, or 
balance, a condition just opposite to that of being dizzy. 
It is probable that this function residing in the middle 
ear is connected with the similar function of the cere- 
bellum. 

Care of the Ears. — One of the most common causes of 
injury to the ears is the attempt to remove earwax from 
the auditory canal by means of pins or other hard sub- 
stances. The ordinary washing and wiping of the ears 
with a towel is sufficient to insure perfect cleanliness, 
while the constant introduction of hard substances is 
likely to set up an irritation which may eventually impair 
the hearing. Currents of cold air blowing into the ears 
may do great harm by chilling the sensitive tympanic 
membrane. The contact of cold water with this mem- 
brane often causes earache, or acute inflammation of the 
middle ear ; for this reason it is always better to place 
pieces of cotton in the ears before diving, or bathing in 
the surf. 



238 THE ESSENTIALS OF HEALTH 

Foreign bodies in the ear are not always easily re- 
moved. Insects are best removed by having warm sweet 
oil gently poured into the auditory canal ; this will either 
drive the insect out or kill it ; in the latter case it can 
then be easily removed. Physicians should always be 
consulted for the removal of other foreign bodies. 

Hearing and Mental Growth. — We can certainly all 
appreciate the value of the sense of hearing. We have 
only to place the hands over the ears for a short time in 
order to understand how differently all things would seem 
to us if we were deprived of this sense. We should not 
only be very careful not to do anything that might impair 
our hearing, but we should also make every effort to 
improve it. The mechanism of the ear itself may be in 
perfect condition, and yet the hearing may be apparently 
impaired. We say the person is inattentive, does not 
answer promptly, seems to be indifferent and listless. 
The center for hearing in the brain may be greatly devel- 
oped by a little care on our part. Pay sharp attention to 
what is said to you. Cultivate the ability to reproduce 
accurately what you hear. Be quick, prompt, alert. 
These are qualities which will contribute in no small 
degree to your future success. 



CHAPTER XXVII 

THE SENSES OF TOUCH; TEMPERATURE; WEIGHT; PRES- 
SURE; COMMON SENSATION; AND PAIN 

The Sense of Touch. — A reference to the chapter on the 
skin will recall the fact that in some of the papillae of the 
skin are nerve fibers; in Fig. 73, at (4), is such a nerve 
termination. These papillae are called the touch cor- 
puscles, as they are especially concerned in the sense of 
touch. It must be remembered, as shown in Fig. 73, that 
there is only a thin layer of cells between these corpuscles 
and the surface of the skin ; therefore, it is readily un- 
derstood that any impression made on the outer surface 
of the skin is almost in direct contact with one of these 
touch corpuscles. 

The touch corpuscles are very numerous on the palms 
of the hands and inner surfaces of the fingers, while they 
are the least numerous on the back. The sense of touch 
seems most acute on the tip of the tongue. It is the 
least complicated of any of the senses and is the one first 
developed in the child. It is in constant use, bringing 
us into the closest relations with external objects. By its 
use we learn the size, shape, solidity, smoothness, and 
many other qualities of bodies. 

The sense of touch is capable of being highly devel- 
oped, especially if great reliance has to be placed upon 
it, as in the case of blind persons. They soon learn to 
read by passing the fingers over raised letters ; to recog- 

239 



240 THE ESSENTIALS OF HEALTH 

nize persons by feeling their faces ; to distinguish plants 
by touching them; and to become expert musicians. The 
blind sculptor Gonelli is said to have modeled beautifully, 
relying on the sense of touch alone. 

Degrees of Acuteness of Touch. — Those parts are most 
sensitive to touch which have the greatest number of 
touch corpuscles. The degrees of delicacy may be meas- 
ured by means of a pair of compasses with blunted points. 
The two extended points are touched at the same moment 
to the skin, while the eyes of the subject are closed; the 
points are gradually brought nearer together by the op- 
erator until the subject feels both points as one, when 
their distance apart is noted. The same experiment can 
be performed, though less accurately, with pins. Two 
pins are held with their points at least an inch apart, and 
then pressed lightly against the skin on the back of the 
wrist of another person. Repeat the experiment, bringing 
the points nearer together each time. Soon the person 
will declare that he feels but one point instead of two. 
The distance between the points will give the degree of 
acuteness of touch for that part of the body. In this way 
it has been proved that the shortest distance at which the 
two points of a compass can be distinguished as double 
is as follows: oil the tip of the tongue, -^ of an inch; on 
the inside of the tips of the fingers, ^ of an inch ; on the 
palm of the hand, about ^ of an inch ; on the cheek, about 
| of an inch ; and on the back, over 2 inches. 

The Sense of Temperature. — The temperature sense 
makes us acquainted with all the variations in the tem- 
perature of the skin. If any part of the skin rises above 
its proper temperature, we feel warm; if it falls below 
it, we feel cold. When a body which takes heat from 
the skin is applied to it, a sensation of cold is produced ; 



THE OTHER SENSES 241 

while if a body which imparts heat is applied, warmth is 
experienced. The sense of temperature appears to be 
principally in the skin, the mouth, the throat, and at the 
entrance of the nose. The appreciation of temperature 
varies for the different parts of the body ; for instance, 
hot applications which would be intolerable on the face 
can be borne when applied to the scalp. 

The sensations of heat and cold are sometimes strangely 
confused. If the hand be dipped in very cold water, and 
then dipped again in water a number of degrees warmer, 
there is first a feeling of warmth and then of cold ; if 
one finger be dipped in warm water, the feeling of warmth 
will not be nearly so great as it would if the whole hand 
w T ere immersed; if a warm piece of iron is placed in one 
hand and cold iron of the same weight is placed in the 
other hand, the cold weight will be declared to be heavier. 

The Sense of Weight. — The muscular sense, or the 
sense of weight, informs us of the amount of muscular 
contraction necessary to lift a body. It depends partly 
on the sense of pressure and partly on common sensibility. 
This sense is, therefore, about midway between a special 
sense and the common sensation of the body described 
below. By placing weights in each hand and then raising 
and lowering the hands, one becomes conscious of a certain 
amount of resistance. The muscular exertion required to 
lift the body gives us the sense of weight;, and by practice 
it is possible to distinguish very slight differences in the 
weights of bodies, even in those as light as coins. 

The Sense of Pressure. — The sense of pressure enables 
us to judge of the amount of weight or pressure, on differ- 
ent parts of the skin. To illustrate this, the hand, or the 
part being tested, must rest on the table, or must be sup- 
ported in some way, while different weights are applied. 



242 THE ESSENTIALS OF HEALTH 

The subject, who is blindfolded, is not allowed to lift or 
to move the hand during this test, as in that way the 
muscular sense would be brought into play too. The 
various parts of the body differ exceedingly as to the 
amount of weight required to make itself felt : the most 
acute portion is the forehead ; next, the temples ; then the 
back of the head; and lastly, the forearm. 

Common Sensation. — The term common sensation refers 
to all parts of the body, which have sensitive nerves that 
are capable of causing pleasant or unpleasant sensations. 
These cannot be compared to the special senses already 
described ; in fact, they are difficult to describe at all. 
We have many of these common sensations, each one of 
a character peculiarly its own ; thus we speak of the sen- 
sations of hunger, of thirst, of pain, of fright, of fatigue, 
of illness, and of health. 

Pain. — If any of the nerves of sensation be disturbed, 
it produces a sensation called pain. If a sensitive nerve be 
cut in any part of its course, this produces pain which is 
always referred to the place where the nerve ends, rather 
than to the point injured. Thus, hitting the ulnar nerve, 
the " crazy bone," at the elbow causes a pain in the little 
finger and part of the adjoining finger, as these are the parts 
in which the nerve terminates. It is not known what 
causes the differences in the varieties of pain; some are 
sharp and cutting, while others are dull and throbbing. 

Pain is a valuable bodyguard. It tells of the approach 
of danger, and points to disease when it is present. It 
may be stated that any so-called stimulus will cause pain, 
if applied beyond the normal limit and to an excessive 
degree. Light is the stimulus for vision ; yet strong 
light, as the glare of the sun, is at once painful. Sounds 
falling on the ear may awake the most pleasant memories; 



THE OTHER SENSES 243 

yet loud and long-continued sounds soon become positively 
painful. The ordinary contraction of a muscle is free 
from pain ; yet the rapid and violent muscular contrac- 
tions in spasms are intensely painful. 

The nerves of sensation are the great protectors of the 
body. Without them and their sensitiveness to pain, we 
should cut, burn, bruise, and otherwise disfigure the body 
in many ways as we go about our daily work. Pain 
keeps us from pursuing many harmful courses, and thus 
aids greatly in protecting the body. 

Animals appear to suffer pain, especially those animals 
which are most noted for their intelligence, such as the 
dog and the horse. The finer bred the animal, so much 
the more susceptible is it to pain. The thoroughbred 
horse appears to suffer, great pain through injury 
and disease, to which the ordinary work horse may be 
comparatively indifferent. Creatures low in the scale of 
animal life do not exhibit evidence that they suffer much 
pain. 



CHAPTER XXVIII 
CIGARETTE SMOKING 

A study of the facts regarding the introduction of 
tobacco into England and from there all over Europe 
would take us back to Sir Walter Raleigh's time. When 
we inquire into the use of cigarettes by American boys, 
we learn with some surprise that previous to the year 
1862 cigarettes were rarely used by boys. Their use 
was first noticed among the students of the Rensselaer 
Polytechnic Institute at Troy, New York, which was 
attended by a number of boys from Cuba and South 
America, who, according to the Spanish custom, smoked 
cigarettes. . They taught the American boys in the insti- 
tution who were foolish enough to learn. From them the 
practice spread over the country until now so many boys 
smoke that there is danger that the American people will 
lose that splendid mental and physical vigor that has made 
the nation what it is to-day; danger that we shall become 
dwarfed in stature and mediocre in intellect. The history 
of the nations where smoking has been universal for a 
considerable period of time points out these dangers. 

Every boy who sings "The Star-Spangled Banner," 
thrilling with pride at the glorious deeds done under it to 
maintain this land of liberty, should remember that no 
foes without are so dangerous to a country as those foes 
within that lower the strength and character of its citi- 
zens. Such a foe is tobacco. 

244 



CIGARETTE SMOKING 245 

Cigarettes are probably the most dangerous form in 
which tobacco is used. The evidence of the harm done by 
cigarettes is too plain to be overlooked. Every few days 
one sees in the newspapers some such headings as, " Ciga- 
rettes drove him Insane"; " Suicide of a Cigarette 
Smoker"; "Dying from Cigarette Smoking"; " Crazed 
by Cigarettes"; " Cigarettes killed Him"; "A Cigarette 
Heart"; " Cigarettes unbalanced his Mind"; "Died from 
Smoker's Heart"; "Tobacco causes Loss of Memory"; 
and so on. 

The above are the actual titles of clippings collected 
during a few months from the daily papers. Among the 
victims of the cigarette thus recorded are : a young Amer- 
ican pastor dying at 29 years of age ; a 39-year-old super- 
intendent of a savings institution, sudden death ; a young 
mechanic, rendered insane; a 16-year-old boy, insane; a 
young man of 22, insane ; a wealthy retired grocer, sent 
to an insane asylum ; a man of 30, meeting the same fate ; 
a 60-year-old Frenchman, dying of tobacco heart ; a young 
German, same trouble ; and so the records go on. Any 
one who will watch the papers will find material for simi- 
lar lists. 

Boys who have already begun to trifle with their life 
and destiny by the use of cigarettes may reply to such a 
list of tragedies that they result from smoking too many 
cigarettes and that a few will not hurt anybody. The 
first use of tobacco is the thin edge of the wedge which 
when once started overcomes resistance. 

But the cigarette, or tobacco in any form, is more resist- 
less even than a wedge, for it can overcome the smoker's 
will to resist. He soon gets where he does not care, 
because the vigor of his mind and body is weakened by 
the tobacco. He smokes when he feels like it, regardless 



246 THE ESSENTIALS OF HEALTH 

of consequences, and he feels like smoking oftener and 
oftener, and more and more. It is the nature of tobacco 
to increase the user's desire for it. 

The most marked effects of cigarettes or of tobacco can 
be seen by the ordinary observer if he is keen and keeps 
his eyes open, but the slower effects and the strange power 
which tobacco, like other narcotics, has of making itself 
craved, are best explained by the physician whose busi- 
ness it is to detect signs of ill health and to understand 
the action of drugs. Here are some of the things the 
doctors say about tobacco : — 

One who, besides being a physician, is a professor of 
physiology, teaching in a medical college, 1 tells this of his 
own personal experience with tobacco, for when a medical 
student himself he thought he must learli to smoke : — 

" I noticed from day to day that during the smoking of 
the cigar there was a perceptible change of mental attitude 
toward my work and toward things in general. I would 
begin a cigar with mind all alert, ambitious to get at 
some work that needed to be done. After a half hour of 
watching the smoke curl up toward the ceiling I was con- 
scious of a falling off of mental activity, and unless the 
work were imperative I usually ended up by taking a half- 
hour stroll down Michigan Avenue to be entertained by a 
glimpse of its equipages and its people. I was conscious 
of a sort of ' don't care ' mental attitude toward things in 
general. 

" I have never for a moment doubted that my change in 
mental attitude was to be attributed solely to the effects 
of the nicotine. I believe, in the light of subsequent 
observation, that it is just this effect of the tobacco which 

1 Winfield S. Hall, Ph.D., M.D., Professor of Physiology in the North- 
western University Medical School, Chicago. 



CIGARETTE SMOKING 247 

makes it especially pleasing to people. If I failed to have 
my after-dinner cigar, I missed it so much that I woke up 
to the fact that I was slowly but surely forming a ' drug 
habit,' and through my medical studies I knew that a 
drug habit, whether for morphine, cocaine, alcohol, or 
other narcotic or stimulant, is harmful to the system in 
direct proportion to its use, and I knew that without ex- 
ception all of these drugs enslave a person by gradually 
undermining his will power ; the more one takes, the less 
he is able to stop. When I realized the situation, I 
stopped." 

In this connection, Dr. T. H. Marble calls attention 
to the fact that in 1898, during the organization of our 
volunteer army, it was found that large numbers of young 
men who were otherwise capable had rendered themselves 
unfit for service by the use of cigarettes. He states that 
among the applicants for active service who were addicted 
to the use of cigarettes the examining physicians found 
it necessary to reject more men on account of disabilities 
thus caused than for disabilities arising from any other 
cause. 

An editorial in the Journal of the American Medical 
Association points to a similar condition in France, com- 
menting : " It is said that the increasing mortality in the 
French army which is stated to be steadily on the increase 
is largely due to pulmonary affections that are themselves 
favored by the general habit of cigarette smoking. Other 
presumable causes are not more active than they were a 
few years ago, but this one evil seems to be constantly 
gaining ground, and is therefore held as mainly responsible 
for the increasing mortality from lung disorders in the 
French army. . . . The practice [of cigarette smoking] 
was originally a Spanish one, and it suggests a query 



248 THE ESSENTIALS OF HEALTH 

whether the misfortunes of the Spanish nation may not be 
due in part to a race degeneracy thus produced. If so, it 
will be well for us and other nations to take warning 
from their example. In these days, also, when wars are 
still in fashion, whatever can diminish the military 
strength of a people is a national calamity." 

Dr. A. C. H. Friedman says: " While the dangerous 
effects of tobacco poisoning are known to affect almost 
every part of the human organism, the result which brings 
the- patient quickest to the physician is the injury which 
it causes in the eye. . . . The most characteristic symp- 
toms of chronic tobacco poisoning are evidenced in the eye, 
and they are all known under the name of ' tobacco ambly- 
opia.' The time necessary for the development of this dis- 
ease is individually different and ranges from six months 
to many years." 

Dr. Kitchen, in the Medical Record of 1890, says that 
the properties of tobacco " have an effect upon the body 
in moderate as well as in immoderate use, the effects being 
simply in proportion to the quantity used, though the 
effects of moderate use may not be measurable by ordinary 
means. It is easy to see the effects of large amounts of 
tobacco in the stunted growth of adolescents, in functional 
cardiac disorders, loss of appetite . . . intellectual slug- 
gishness, loss of memory, color blindness, marked blunting 
of various functions of sensation." 

Many boys begin the use of tobacco before they are 
old enough to know or understand the harm it does. 
They are not qualified to judge of its effects upon those 
they see using it. They seem to be a good deal like 
sheep ; there is an old saying that if one sheep of a flock 
goes over a stone wall, the rest are sure to follow. Espe- 
cially are boys given to doing what they see men do. 



CIGARETTE SMOKING 249 

They do not stop to think whether they are imitating a 
man's virtues or his vices. 

Dr. Bartholow, Professor of Medicine in Jefferson 
Medical College, says : u Every man, when he smokes in 
public, ought to think that he is thereby encouraging some 
boy to smoke. . . . Tobacco in any form is a great in- 
jury to a growing boy, and the fashion of inhaling the 
smoke and then forcing it through the nose is deadly in 
its effects. It causes catarrh in the air passages and 
makes the smoker disgusting as well as puny and stunted. 
You will find that these cigarette-smoking youths have 
impaired digestion, small and poor muscles, irritable tem- 
pers, and a lack of capacity for sustained effort of any 
kind, and I believe that you will find that they do not 
succeed in life. The men who win are men of strong phy- 
sique. A cigarette-smoking boy will not make a strong 
man." 

Every well-informed boy knows that tobacco is for- 
bidden to men who are training for games and races. 
The reason is that tests and experience have shown that 
tobacco weakens the muscles and makes one incapable of 
doing his best. This fact is coming to be well known by 
business firms who employ men and boys, and it is closing 
many desirable positions to those who use tobacco. 

The effect of tobacco upon efficiency is the same whether 
a man is working for himself or for others. 

When a business man advertises for a boy, he looks over 
the applicants that come, and no recommendation that a 
boy can bring will offset the tell-tale marks of tobacco 
stains on his fingers. The business man has learned by 
experience that the boy who smokes is likely to shirk his 
duty when no one is watching ; his trustworthiness can- 
not be relied upon. 



250 THE ESSENTIALS OF HEALTH 

The qualities which the employer looks for in the boy- 
he selects are the ones that are most essential to the boy's 
own success if he is struggling independently to win the 
best prizes in life. In whatever way he works, tobacco 
holds him back. 

Dr. E. Stuver, President of the Wyoming Scientific 
College, states that in his observation and experience the 
use of tobacco has a peculiarly demoralizing effect on the 
moral nature of the young. He says further : " In addi- 
tion to making boys tired, stupid, and lazy, it makes them 
irritable, perverse, and careless of the rights and feelings 
of others, besides in many instances leading to lying and 
even stealing. This tendency to moral degradation is 
exceedingly prevalent among habitues of all kinds of 
narcotic poisons." 

Another physician, Dr. Matthew Woods, of Philadel- 
phia, adds the following to the list of the bad effects of 
tobacco upon the brain : He says it weakens the power of 
achievement, soothes the excited nerves only to render 
them ultimately more irritable, weakens self-restraint and 
will power, perverts the taste, diminishes mental capacity, 
corrupts the moral sense, stimulates the animal nature, 
causes inferior scholarship in students, and takes away the 
sense of shame in failure. He finds that it " banishes that 
beneficent discontent which is the originator of reform, 
the maker of beauty; without it we retrograde, with it 
we advance. . Discontent is a progress-provoking quality. 
It was discontent that invented the spade, the harrow, the 
plow. It created the locomotive, replaced the galleon 
by the steamer, the postilion by the telephone. The 
studiousness of the scholar, ardor of the poet, sacrifice of 
the patriot, fire of the hero, and the rapture of the saint 
are all due to the presence of rest-preventing discontent ; 



CIGARETTE SMOKING 251 

and yet so oblivious are we of its value as a means of con- 
quest and development, that instead of having it instigate 
to the removal of obstacles, like our elders, Ave merely 
aim to destroy it with a drug ; we put an enemy in our 
mouths to steal it away, and thousands of young men as 
a consequence, under the spell of its artificially induced 
calm, fail in the race of life as the great w r orld with its 
struggles and aspirations moves on." 

There is no class of people who see more clearly than 
the educators of the country the bad effects of tobacco 
upon the young. The testimony of an experienced 
school principal, Professor H. H. Seerley, of the Iowa 
State Normal School, clearly expresses what every observ- 
ant teacher can corroborate. He writes: "After making 
a study of several hundred boys, running through a period 
of ten years, I give only observed facts, and neither assume 
the conditions nor jump at foreordained conclusions. 

" 1. Boys that begin the habit at an early age are 
stunted physically and never arrive at normal bodily 
development. 

" 2. Accompanied with the use of the narcotic were 
certain disordered physical functions, such as indigestion, 
impaired taste, defective eyesight, dulled hearing, nervous 
affections, and diseases of the heart. I have not found a 
single case of early addiction to the habit of tobacco using 
that did not suffer with one or more of these direful 
abnormal conditions. 

" 3. Tobacco, used in any form, destroyed the abilitj^ 
of a pupil to apply himself to study, and prevented his 
comprehending or remembering his lessons. The mental 
faculties of a boy under the influence of the narcotic seem 
to be in a stupor, and since depraved nerve power 
stultifies and weakens the will power, there is but little use 



252 THE ESSENTIALS OF HEALTH 

for the teacher to seek to arouse the dormant, paralyzed 
energies or to interest and foster the fagged desire. I 
have not met a pupil that is addicted to the habit who 
will go through a single day's work and have good lessons. 
I have not had one whose scholarship record was good, 
and in almost every case the deportment was below the 
average standard. At the regular examinations for pro- 
motion, nearly every one of the tobacco-using pupils fail 
in doing the most reasonable test work, even if this is 
not the first time the work has been passed over in class. 
I have had numbers of cases in which they have remained 
in the same grade for four successive years, and then they 
were not ready to be advanced into the next higher class." 



CHAPTER XXIX 
SOME ESSENTIALS OF HEALTH 

The Control of our Bodies. — Our study in the preceding 
pages of the elementary truths of physiology has not been 
complete unless we have observed that the first purpose 
there has been to explain the working of our bodies and the 
laws of health governing them ; and the second purpose, 
to show that it is only by the use of discretion and the 
exercise of our will power that we can keep our bodies 
and minds in the best possible condition. 

What every boy and girl, should aim to do is to put his 
body under the control of his mind in matters relating to 
his own health. That is to say, he should so apply his 
understanding of the uses of the various organs of the 
human body and the effects of this or that treatment upon 
them, that he is able for the most part to avoid those 
things which will be harmful to his health and cultivate 
those things which will help to upbuild his physical and 
mental manhood. For physical manhood is the founda- 
tion upon which mental and moral manhood must rest. 
Control of our own bodies, then, based upon a proper 
understanding of them, is the first step toward the attain- 
ing of our manhood or womanhood. 

We have seen that the brain is the seat of the mind, 
and though we may not understand all the physical 
operations of this wonderful organ, we do know that by 
means of its agents, the nerves, which connect it with 
all parts of the body, it largely controls our voluntary 

253 



254 THE ESSENTIALS OF HEALTH 

muscles and therefore our actions. We must will to do 
a thing before we can do it. Thus we see how important 
it is for us to keep the brain in a healthy state, for this 
means keeping the mind clear and active for its work of 
controlling the body. 

The Deceptions of Alcohol. — We have already noted 
that alcohol taken into the body, while it is capable of 
affecting almost every important organ, produces its 
quickest and most disastrous effects upon the brain and 
the nerves. We saw how its first effect is that of a quick- 
ening of the circulation in the brain, giving the one who 
uses it a feeling of exhilaration which he is apt to mistake 
for a real increase of mental power. 

As a matter of fact the effect of alcohol upon the whole 
system is in the beginning a series of dangerous deceptions, 
With the quickened action of the heart and the rush of 
blood to all parts of the body, a feeling of strength is 
given, when in reality the individual is made weaker. A 
sense of intellectual power is felt for the moment, when 
the mind is actually being clouded and dulled. A feeling 
of warmth is imparted, when the blood is in reality being 
rapidly cooled. A feeling of power over himself and 
others deceives the individual, for he is really less able 
either to control himself and his own lower appetites or 
to resist temptations offered by others. As more and 
more alcohol is taken into the system, the brain is affected 
more and more, and the control of the mind over the body 
becomes less and less effective. Evidences of this are 
seen in the individual's speech which becomes rambling 
and loose because of his inability with his impaired brain 
to think clearly and consecutively ; and in the loss of the 
control of the mind over the muscles of the body, to such 
an extent that he can neither stand nor walk steadily. 



SOME ESSENTIALS OF HEALTH 255 

If when the individual reaches this state he takes still 
more of the poisonous liquid, he finally loses all conscious- 
ness and consequently all control over his movements. 
Thus he, for the time being, is as far removed as possible 
from the first step toward the attainment of his man- 
hood, — the mastery of his own body. Such a condition 
is, of course, only reached by the use of large quantities 
of liquor at any one time. 

Small Quantities impair Control. — But what effect have 
alcoholic liquors when used in smaller quantities upon 
the ability of the mind to control the body? It is a 
physiological fact, as has been pointed out, that the con- 
tinued use of alcoholic drinks, even in small quantities, 
impairs the delicate brain cells and therefore to that extent 
weakens the supremacy of the mind over its servant, the 
body. It is not sufficient to point to this or that " moder- 
ate drinker " who has achieved conspicuous success in life, 
for what is there to show but that his success might have 
been greater had he kept his brain free from all influences 
of this poison. Moreover there is abundant testimony of 
habitual but so-called moderate drinkers to the effect that 
their usefulness has been impaired and their mental powers 
weakened by the constant use of alcoholic beverages. 

Dangers of the Social Glass. — And what of the man 
who uses alcohol neither in large quantities, nor habitually 
in small quantities, but who takes a glass occasionally for 
the sake of good fellowship or under pressing invitation ? 
The danger in such cases, of course, arises from another 
cause. It must always be borne in mind that there is in 
the nature of this narcotic the power to create a demand 
for itself in the system, the power to create an appetite 
for itself that insists upon being gratified. The real peril 
to the man who takes a single drink is that he is trifling 



256 THE ESSENTIALS OF HEALTH 

with a substance which has the power to fasten a fatal 
appetite for itself upon him. 

To the " moderate" drinker also there is ever present the 
danger that he may sooner or later lose control of his will 
power and drink more than he intends. For as we have 
already noted, the man who takes one or a few drinks 
may be so mentally weakened, that he is less and less able 
to exert his self-control to resist the impulse to drink more. 
He becomes more and more careless and reckless, less and 
less considerate of consequences. We are not going too 
far, therefore, when we make the broad assertion that the 
use of alcoholic drinks is always likely to result in an im- 
pairment of the operations of the brain and a consequent 
loss of control over the body. The man who uses them, 
therefore, does so at the tremendous risk of debasing his 
own manhood. 

The Strengthening of Character. — But there is another 
side to this serious question. Not only is the man who 
takes a firm stand against all use of alcohol in any form 
and in any quantity free from the danger of finding him- 
self unable to exercise his usual self-control, but he is 
actually strengthened in character each time by his re- 
fusal. After a time the refusal becomes less difficult to 
make and to stand by,. and he comes to a fuller realization 
of his own ability to do what he knows is for his own 
physical and mental health and happiness. 

There are many historical instances of men of genius 
whose promising careers have been cut short and whose 
lives have been utterly ruined by the loss through strong 
drink of this one power of mind, — the power of self-con- 
trol. And there are many more instances in which men 
of great minds have achieved continued success in life by 
their firm refusal to indulge an appetite which they real- 



SOME ESSENTIALS OF HE ALT II 257 

ized could lead only to their physical and mental undoing. 
Thus when the old Trojan hero Hector, on being overcome 
at saving farewell to his loved ones, was offered wine by 
his mother, he said to her, " O venerable mother, bring me 
no caressing wine to unnerve me and make me forget 
courage and strength." 

Tobacco dulls Ambition. — What has been said of the 
cultivation of our powers of self-control in abstaining 
from the use of any form of distilled or fermented liquors 
may be . said also of the use of tobacco. Of course the 
injurious effects of tobacco upon the system are not so 
destructive as those of alcohol. But we have seen in 
previous chapters that tobacco has, though in a less degree, 
the same effect upon the heart, causing the blood to flow 
more quickly and resulting in a slight rush of blood to 
the brain. There follows a dulling and soothing effect 
upon the mind, which robs it of ambition and energy and 
gives a feeling of contentment and self-satisfaction where 
there should be a feeling of eager unrest and the strong 
desire to accomplish something. It has been demon- 
strated beyond question that the continued use of tobacco 
by the young weakens the mental powers of the individ- 
ual by its effect upon the brain. It gives an artificial 
peace of mind in place of a pressing desire and a strong 
will to achieve success. To just the extent that one's will 
power is weakened by the use of this narcotic will his 
power and control over his own body be impaired. 

The Weakening of Mental Force. — And this is entirely 
aside from its many other injurious effects upon the 
system, — effects upon the digestion, the heart, the lungs, 
the nerves, the eyes. Therefore, as in the case of alcohol, 
though in less degree, we may say that the boy or the man 
who uses tobacco becomes through the impairment of his 



258 THE ESSENTIALS OF HEALTH 

mental forces less and less the complete master of his own 
body. Especially is this true in the case of the boy who 
uses it. His mind is then in the process of development 
and is in consequence more easily affected. As illustrated 
in Chapter XXVIII, instances are all too frequent in which 
boys addicted to the habit have become incapable of clear 
thinking, have largely lost their memory, and have had 
their will power so seriously weakened that they are 
unable to stand for things that are right against things 
that they know to be wrong. Indeed, not a few cases 
could be given in which the use of cigarettes has led to 
the complete loss of the reason. 

All this teaches us that if we are to maintain the proper 
supremacy^ of the mind in its mysterious relation of 
control over the body, and thus develop our physical and 
mental manhood, we must carefully avoid those things 
which tend even in a slight degree to clog the operations 
of the brain and to destroy our self-control. 

Habits of Health. — We have already noted that habits 
are formed by the frequent repetition of the same act. 
When we see an object or hear a sound for the first time, 
our attention is attracted to it by reason of its novelty. 
But if we pass the object or hear the sound every day, it 
soon ceases to make any impression upon us. And so it 
is with those of our actions which become habits. By 
constant repetition they become so much a part of us that 
we sometimes speak of our strong habits as being " second 
nature" with us. 

Perhaps the most important thing for the boy and the 
girl, who in a few years will be the man and the woman, 
is the formation of what we may call habits of health — 
that is, habits of doing those things which will upbuild and 
strengthen the body and keep it in healthy condition, 



SOME ESSENTIALS OF HEALTH 2o9 

and habits of refraining from the things which will impair 
and weaken the body and interfere with the operation of 
the laws of health. 

Habits of Imitation. — We all know that a very young 
child learns by imitating those about him many of the daily 
acts which soon grow to be habits, requiring little or no 
thought. He learns to talk by imitating the sounds his 
elders make in speaking. He learns to walk, to play, to 
sing, in much the same way. Indeed, almost all of his 
earlier acts are imitative, and those about him are con- 
stantly surprised by this or that thing that he " picks up" 
from observation of older people. Even in later life 
many of our acts are imitative, and, therefore, many of 
our habits are formed by copying those with whom we 
come in contact. But when we have grown old enough 
to distinguish between good habits and bad habits, 
between healthful habits and habits injurious to health, it 
becomes our duty to imitate only those acts which we 
know to be helpful or at least harmless, and to refrain 
from imitating those which we know to be hurtful to our 
bodies or our minds. 

The Forming of Narcotic Habits. — Many a young man 
takes his first drink and many a boy smokes his first ciga- 
rette because he sees those about him, perhaps his elders, 
doing the same thing, and he thinks it manly and big to do 
what others are doing. In fact there is often a little zest 
added to the act because he knows that he is treading on 
dangerous ground. He does not stop to consider what he 
has learned about the effect of these things upon his body 
and mind. He feels so strong and well that it seems ab- 
surd to be casting about for possible results in the future. 
He does not stop to think that ninety-nine out of a hundred 
of those physically and mentally wrecked by the use of 



260 THE ESSENTIALS OF HEALTH 

these narcotics made their beginning in just this same way, 
with the same belief in their power not to form the habit 
and not to yield to it. 

But the appetite is aroused, and the habit begins slowly 
to twine itself about him. It requires an effort of the 
will to break away from any habit, because it is much easier 
to do what we are accustomed to do than to follow a new 
course of action. Especially is this true in the case of the 
tobacco and drink habits, for not only may a consuming 
appetite for these things be created by their use but, as we 
have seen, the will power itself is likely to be steadily 
weakened and broken down. Many a prisoner in the 
chains which these habits forge about their victims declares 
himself powerless to shake off the bands which have bound 
him, in spite of his honest desire to do so. 

Importance of forming Helpful Habits. — The majority of 
the habits which are formed for life fasten themselves upon 
us in boyhood and girlhood or in early manhood or woman- 
hood. These are the times in our lives, therefore, when 
we should be most careful. But it is not sufficient simply 
to avoid the formation of injurious and pernicious habits; 
we must also seek to attach to ourselves those habits which 
we know will best promote our physical and mental 
prosperity. 

We must cultivate habits of cleanliness, habits of tem- 
perance and regularity in our eating and drinking, habits 
of proper respiration, habits of muscular and mental exer- 
cise, habits of rest and sleep. The necessity to the human 
body of all of these things has been pointed out elsewhere. 
What we want to emphasize here particularly is that by 
forming these habits of health in youth they become so 
much a part of our everyday life that it is only by an effort 
of the will or by some unavoidable circumstance that we 



SOME ESSENTIALS OF HEALTH 261 

depart from them and incur the danger of illness. Our 
bodies are thus made and kept the strong and healthy 
servants of our minds. 

What is Success? — Every right-minded boy and girl who 
stops seriously to consider the life upon which he is start- 
ing out desires to make a success of that life. But it will 
be found that people vary very widely in their ideas of 
what success is. It is a much too common notion that 
success in life means the amassing of a fortune or the 
attainment of some high position among our fellow-men 
where we can be constantly in the public eye. 

As a matter of fact neither of these things is to be de- 
spised, but it is certainly true also that neither of them is 
a real test of any man's success in life. It is neither pos- 
sible nor desirable that all of us should become million- 
aires, nor that all of us should become famous men. For 
most of us the sphere of our reputation and influence 
must be comparatively small — indeed, in many cases must 
be largely restricted to the community in which we live. 

What, then, should be the success toward which each 
of us ought to labor ? On this point the president of one 
of our great American universities has this to say: "In 
every walk of life, strength comes from effort. It is a 
habit of self-denial which gives the advantage to the man 
we call self-made. He is often very poorly put together. 
His education is incomplete ; his manners may be un- 
couth. His prejudices are often strong. He may wor- 
ship himself and his own oddities. But if he is successful 
in any walk in life, he has learned to resist. He has learned 
the value of money, and he has learned how to refuse to 
spend it. He has learned the value of time, and how to 
convert it into money, and he has learned how to resist all 
temptation to throw either money or time away. He has 



262 - THE ESSENTIALS OF HEALTH 

learned to say 'No.' To say 'No' at the right time, and 
then to stand by it, is the first element of success." 

The First Element of Success. — Of course there are 
many elements which go to make up the character of the 
successful man. But the ability to say " No " is the first 
and most important of them all. And since the enjoyment 
of a sound mind in a healthy body is absolutely necessary 
to the development of our powers, we must learn above all 
things to say "No" to those things which we know to be 
injurious to our bodies and our minds. Surely it is un- 
necessary for us again to point out that the most injurious 
and dangerous of all the vices against which our civiliza- 
tion has to battle is the use of the narcotics, alcohol and 
tobacco, which, take such firm hold upon many of those 
about us. 

The Habit of Work. — Next to a clear brain and a 
strong body the thing most needed to win success is the 
willingness to work. Every boy and girl should guard 
against the formation of careless and shiftless habits and 
indulgence in laziness. We appreciate most the things we 
work hardest to win. Indeed, we may say that no success 
in life is achieved without work. This does not mean that 
if we work, we shall always accomplish our desire, always 
attain our goal. But it does mean that in spite of our 
occasional failures we shall make ourselves useful to those 
about us, and the world a little better for having lived in 
it. And that is real success in life. 

Degrading Habits ; Narcotics. — Finally, let us bear in 
mind that good health and unimpaired mental powers are 
not the only rewards of keeping' our bodies from the de- 
stroying effects of alcoholic drinks and tobacco. Perhaps 
their most serious effect is upon the moral nature of their 
victim. The man who uses alcoholic drinks tends to lose 



HOME E88ENTIAL8 OF HEALTH 263 

his finer Bensibilities and to become more and more de- 
graded in thought and action. In appearance and in 

conduct the drinker becomes less and less like the noble 

being for whom he was intended, and more and more like 
the brute. A visit to any of the criminal courts of our 
large cities will convince us of the large percentage of 
crime committed by those who have reached the depths 
of moral degradation through the use of strong drink. 

In regard to tobacco it has been proved that its use by 
boys often results in a dulling of the moral sense until 
they are scarcely able to distinguish between right and 
wrong. Our many reformatories for the cure of youthful 
degenerates who have been morally deranged by excessive 
smoking offer abundant evidence of this. 

To become the right kind of man or woman requires a 
personal choice on our part between right and wrong. 
The reward of right choice is good health and success in 
life; the result of wrong choice is ill health and failure. 
Real success cannot be attained without constant self- 
mastery, but that goal abundantly justifies the effort to 
reach it. 



{Supplementary Chapters) 

CHAPTER XXX 
EMERGENCIES 

In cases of emergency it is necessary to act promptly 
and properly, the first requisite being presence of mind. 
Remember how necessary it is that the body should at all 
times be supplied with an abundance of pure air. Keep 
in mind also that tight clothing about the w^aist or neck 
may interfere with respiration, even when there is plenty 
of fresh air for the sick person to breathe. In all cases 
of sudden illness, bystanders should be kept at a distance. 
It is not the time to indulge in curiosity. All who are 
not needed will show good sense by stepping away. 

If there is vomiting, turn the person on his side, with 
the head bent down a little, in order to prevent choking. 
There is a popular notion that the first thing an injured 
person needs is an alcoholic stimulant. To act upon this 
idea is both incorrect and dangerous. Let the question 
of giving drugs rest with the surgeon. 

Bites from Animals. — When one has been bitten by 
any animal, the wound should be promptly and thor- 
oughly cleansed. It is better to consult a physician about 
wounds made by animals, as they may be serious. 

Bleeding. — When the skin is broken by either a cut 
or a bruise, blood comes quickly to the surface. If the 
wound is not serious, the flow of blood will slacken, and 

265 



266 THE ESSENTIALS OF HEALTH 

gradually stop. Before treating any wound the hands of 
the operator should be thoroughly washed, and everything 
brought in contact with the wound should be very clean. 
Bathe the wound with the purest water obtainable. The 
object of bathing these slight wounds is to remove all for- 
eign substances and to make the wound as free as possible 
from germs. If the wound is not serious, it is only 
necessary to cleanse it with water, and then bring the 
edges of the wound into their natural position by means 
of strips of adhesive plaster, over which should be placed 
a bandage made from some clean cloth. 

Often, however, bleeding from a wound may be so 
severe that the first object must be to check the flow of 
blood. Remember that bleeding can usually be checked 
by elevating the wounded part above the level of the 
heart. To illustrate : If the finger has been cut, do not 
allow the arm to hang down by the side, but hold the 
hand up as high or higher than the level of the heart. 
Directly over the wound apply a firm compress of the 
best and cleanest material at hand. 

Ordinary wounds heal quickly, if they are free from all 
foreign matter and are made absolutely clean at the start. 
A great many antiseptic washes may be recommended, but 
for all ordinary purposes pure water is sufficient. Water 
which has been boiled and then cooled is the best. Car- 
bolic acid is often recommended and used, but it is a 
strong poison, and should not be kept about the house. 

The remarkable success of the Japanese surgeons in 
their treatment of wounds during the war between Russia 
and Japan has taught us anew that perfect cleanliness is 
the great secret in the treatment of wounds. Everything 
that comes in contact with a wound in any way should be 
perfectly clean. 



EMERGENCIES 2#? 

From an Artery. — Most of the arteries lie deep in the 
body, and consequently they are not frequently wounded. 
When an artery is cut, the blood will flow in spurts or 
jets, and the color of the blood will be a bright red. As 
a rule, nearly every wound of an artery is of sufficient 
importance to require the immediate attention of a sur- 
geon. Until the surgeon arrives there are three things 
to do : (1) have the person lie down ; (2) elevate or hold 
up the wounded part if possible ; (3) press on or near the 
wound with the fingers until a compress or firm bandage 
can be provided. It is better to apply the compress a very 
short distance from the wound, and on that side of the 
wound toward the heart. This leaves the wound free to 
be properly cleansed and bound up. 

From the Capillaries. — When the capillaries are 
injured, blood simply oozes from the surface. The blood 
that comes when the skin has been scraped, is an illustra- 
tion of capillary hemorrhage. The treatment is usually 
very simple. Often mere exposure to the air will check 
the flow. Water, either very hot or very cold, may be 
applied if necessary. Placing a pad or compress directly 
over the wound will also check the blood. 

From a Vein. — From an injured vein the flow of 
blood is steady and not in spurts. The treatment is the 
same as that for bleeding from an artery, except that the 
pressure should be on the side away from the heart. 

From the Lower Extremity. — A person who has 
been wounded in the leg should lie on his back with the 
wounded leg held up, or the leg may be supported on a 
high box or step, as illustrated in Fig. 103. If the injury 
is in the foot, and the bleeding continues after the leg is 
raised, apply a bandage, beginning to wind it at the toes, 
and continuing it a short distance past the wound. 



268 



THE ESSENTIALS OF HEALTH 



If the bleeding is from the leg, apply pressure over 
the femoral artery, as shown by the little square pad in 
Fig. 104. Then put a clean bandage, made from strong 
cloth, around the leg and over the compress, as illustrated. 
Place a stick in the bandage and twist it until the flow 



Fig. 103. 



Fig. 104. 





Fig. 103. — Elevation of leg to control bleeding. 

Fig. 104. — Compress applied over femoral artery of thigh. 



of blood ceases, or until the bandage is very tight. This 
bandage should not be used longer than may be necessary. 

When the foot is injured by broken glass, ragged tin, or 
any such substance, it is wise to call a surgeon and so 
make sure that all foreign matter is thoroughly removed. 
Wounds from rusty nails, toy pistols, etc., often become 
very serious because these substances frequently carry 
poisonous germs with them when they enter the flesh. 

Should a foot become crushed by a wagon wheel passing 
over it, or a heavy weight falling upon it, do not attempt 
to take off the shoe, but send for a surgeon at once. If 
there is much bleeding, raise the foot and apply a compress 
over the femoral artery if necessary. 



EMERGENCIES 



269 






From the Upper Extremity. — When hemorrhage 
occurs from the hand or forearm, the arm should be 
raised above the head. If the bleeding continues, a com- 
press should be applied over the brachial artery. Employ 
the bandage and the stick in the same manner as recom- 
mended for the femoral artery. 
Sometimes it is useful to place 
a compress in the armpit, and 
bind the arm down to the side, 
thereby making firm pressure 
upon the axillary artery, as shown 
in Fig. 105. 

From the Head. — Make 
pressure with the fingers di- 
rectly down upon the bone on 
the side of the wound nearest 
the heart, if an artery is in- 
jured ; and on the side away 
from the heart, if a vein is injured. 




Fig. 105. — Pressure upon the 
large vessels in the armpit 
by a compress. 



Make a small pad 
and place it directly over the wound, holding it in position 
with a bandage passed snugly around the head. 

If an artery of the face is injured, place pressure upon 
the artery where it crosses the lower jaw, which is about 
one inch in front of the angle of the jaw. 

From the Lungs. — In a case of hemorrhage from the 
lungs, call a physician at once. Have the person lie down 
with his head and shoulders raised. He may be given 
half a glass of cold water in which has been dissolved a 
teaspoonful of salt. 

From the Nose. — Bleeding from the nose will gener- 
ally check itself, if the person remains quiet for a short 
time in the sitting posture. Cold water may be applied 
to the forehead and over the nose, or to the back of the 



270 THE ESSENTIALS OF HEALTH 

neck. Or, press the nostrils together for a few moments, 
breathing through the mouth. Or, place the hands and 
feet in water as hot as can be borne. Do not blow the 
clots from the nose, but allow them to remain a few hours 
until all danger of renewed bleeding has passed. If bleed- 
ing still continues after these remedies have been tried, a 
physician should be called. 

Bruises. — Bruises are commonly called black-and-blue 
spots. If the bruise is slight, cloths wet in cold water 
should be placed over it. If severe, hot water and hot 
poultices are better. Sometimes bruises are fatal, even 
when there is no break in the skin; the injury may be 
sufficient to produce serious damage to internal organs. 
Severe bruises demand the prompt attention of a surgeon. 

Burns. — In a case of burning, if the burned part is 
covered with cloth, great care must be used in removing 
this cloth so as not to pull off any of the skin. If the 
cloth adheres firmly, allow it to remain, cutting away all 
unattached portions. Where there are blisters, open them 
with a new and perfectly clean needle, and gently press 
out the water. If the burn is slight, cover the parts with 
cloths wet with water in which has been dissolved as much 
baking soda as the water will take up, and change these 
cloths frequently. When the burn is more severe, saturate 
the cloths with a mixture composed of equal parts of sweet 
oil and lime water. If these lotions are not at hand, an 
application of cream or ordinary machine oil will give 
partial relief. Cover the injured part with gauze, soft 
cotton cloth, or other light material. 

If a person's clothing is on fire, he should lie down 
quickly and roll over and over on the floor. Under no 
circumstances should he remain in an upright position, as 
the flames tend to rise and surround the face, thus causing 



EMERGENCIES 271 

great disfigurement or fatal choking. If a coat, rug, or 
blanket is at hand, this may be quickly thrown about the 
body before rolling upon the floor. If another person is 
present, he should throw the nearest available wrap over 
the burning parts ; and he should not hesitate to throw 
the injured person down forcibly, if necessary, as the 
danger is immensely increased by standing or running. 
In approaching a person whose clothing is burning, it is 
wise to hold a rug, blanket, or coat before one's body as a 
protection. 

Sunburn is the same as any other burn, only it is of 
slight degree. The treatment consists in applying the 
soda solution or in covering the parts with unsalted butter 
or vaseline. 

Convulsions. — Small children and babies occasionally 
have convulsions or fits because of some irritation in the 
alimentary canal, and also from other causes. As soon as 
the convulsion occurs, the child should be quickly placed 
in water as hot as can be borne. The hot bath will usu- 
ally stop the convulsion at once. The child should be 
kept in the bath for several minutes, and then should be 
thoroughly dried, warmly covered, and placed in bed. If 
another convulsion occurs, the same treatment should be 
repeated. A physician should always be called. 

Dislocations. — If there is any reason to believe that a 
joint has been dislocated, the injured parts should be 
kept perfectly quiet until the surgeon arrives. Do 
not handle the joint, as serious damage may be done in 
that way. 

Drowning. — If the heart still beats when the person is 
removed from the water, there is a possibility of saving 
his life. As the beating may be so faint that it cannot 
easily be discerned, it is always best to assume that the 



272 



THE ESSENTIALS OF HEALTH 



heart still beats, and to begin with artificial breathing at 
once. As soon as the person is taken from the water, 




Fig. 106. — First position in artificial respiration — inspiration. 

lay the body face downward. Put your arms about the 
waist and partially raise the body, moving it quickly up 




Fig. 107. — Beginning the movement of expiration. 

and down a few times ; this allows the water to run out 
of the mouth and throat. This should not occupy longer 



EMERGENCIES 



273 



than a part of a minute. Then proceed with artificial res- 
piration (Fig's. 106, 107, 108), as follows : — 

Place the person on his back with a roll of cloth under 
the shoulders. Kneel at his head, and grasp his arms at the 
wrists. Draw them slowly over the head, and hold them 
there long enough to count four deliberately. This raises 
the chest walls, and allows the air to rush into the enlarged 
thoracic cavity. Then push the arms down again, firmly 
but gently against the chest, holding them in that posi- 
tion long enough to count four as before. This movement 




Fig. 108. — Final position in artificial respiration — expiration. 

diminishes the size of the thoracic cavity, and pushes out 
the air. The case should not be abandoned until the arti- 
ficial respiration has been tried for at least two hours. The 
tongue generally falls back into the throat, and prevents 
the passage of air into the lungs. To remedy this, have 
an assistant grasp the tongue with a dry handkerchief and 
draw it out of the mouth. 

Fainting. — The principal thing to remember in cases 
of fainting is that there is not enough blood in the brain. 
Therefore those things should be clone that will promote 
the flow of blood to the head. Usually all that is neces- 



274 



THE ESSENTIALS OF HEALTH 



sary is to place the person on his back and keep the head 
low, certainly as low as the body ; do not raise his head 
until consciousness has returned. Never give alcohol 
or any alcoholic liquor. Dashing a little cold water in 
the face may give aid. If a person feels faint in a public 
place where it is difficult to get to the air, the faintness 
may be remedied by leaning the body forward for a few 
minutes, with the head between the knees. 

Foreign Bodies in the Ear. — When an insect is in the 
ear, it will often leave if a bright light is placed a few 

inches from the 
opening. If this 
fails, the ear 
may be gently 
syringed with 
warm water, or 
a few drops of 
warm sweet oil 
may be poured 
in. If the for- 
eign body is 
anything which 
might swell, a 
bean, for in- 
stance, no water 
should be used. 
Any small particle may fall out if the head is turned 
on the side with the affected ear down, especially if the 
head is shaken. In case this experiment fails, the removal 
of the substance should be left to a surgeon. 

Foreign Bodies in the Eye. — To remove foreign bodies 
from the eye, close the eye and allow the tears to accumu- 
late. When the eye is opened the extra flow of tears will 




Fig. 109. — Showing how the upper eyelid should be 
held, preliminary to turning it over. (The next step 
is to lay a match on the lid and turn it over the match.) 



EMERGENCIES 



275 



cinder 



often wash out the foreign substance. If the substance 
seems to be beneath the lower lid, let some one take hold 
of the lower eyelashes and pull the lid down while the 
patient looks up. In this way the inner surface of the 
lower lid is exposed, and the particle can be gently re- 
moved with the corner of a handkerchief. If it is beneath 
the upper lid, its removal is generally more difficult. By 
grasping the upper eyelashes the lid may be pulled down 
over the under one, and frequently the body may thus be 
removed. If this fails, 
the upper lid may be 
turned and its inner sur- 
face examined. To do 
this have the person look 
down ; then with some 
small article, as a match, 
press upon the middle of 
the lid, at the same time 
grasping the upper eye- 
lashes and turning the 
lid up and over the 
match. This method is 
illustrated in Figs. 109 and 110. If a foreign body is on 
the exposed surface, it can be easily seen paid removed. If 
the particle is embedded in the substance of the eyeball 
itself, a surgeon should remove it. It is unwise to rub 
the eye when any foreign body is in it, as this may embed 
the particle more deeply in the tissues. After the removal 
of a foreign body, a sensation as if it were present often 
remains for several hours. 

Foreign Bodies in the Nose. — To remove foreign bodies 
from the nose, try closing the clear side of the nose and 
blowing forcibly through the other. If this fails, sneezing 




Fig. 110. — Showing where a cinder often 
lodges on the upper lid. 



276 



THE ESSENTIALS OF HEALTH 



can be excited by tickling the nose with a feather, or by 
inhaling a little snuff. As no immediate danger need be 
feared, more active measures should be postponed until a 
physician can be consulted. 

Foreign Bodies in the Throat. — The expulsion of foreign 
bodies from the throat can be aided by holding the child 
by the feet, head down, slapping him sharply on the back, 
and even jerking him up and down two or three times. If 
the body has passed into the windpipe there is great dan- 
ger, and a surgeon must be summoned at once. This con- 
dition will be indicated by short, spasmodic coughing and 
the dusky appearance of the face. 

Fractures. — When it is known or feared that a bone is 
broken, place the person in a comfortable position until 

the surgeon comes. It 
is better to wait a few 
hours for his arrival 
rather than to handle 
the parts in order to 
learn what the matter is. 
If, however, it is neces- 
sary to move the person 
at once, make an arti- 
ficial support for the 
fractured bones. Place the parts in as natural a position 
as possible and put around the limb an even and thin 
layer of cotton, or wool, or other soft material. Place 
over this a number of pieces of lath, or strips of paste- 
board, or any hard substance which will give firm support. 
The length and widtli of these splints must be regulated 
by the size and location of the bone injured. Bind the 
splints to the limb with anything which can be used as a 
bandage. In a fracture of the leg the injured limb may 





Fig. 111. 



- Temporary bandage for a 
fractured leg. 



EMERGENCIES 1^77 

be placed on a pillow, the sides of the pillow brought up 
around it, and strips of cloth passed around the pillow, 
pressing it firmly against the leg, as shown in Fig. 111. 
Or if the accident occurs in the open air, where pads and 
pillows are not available, coats may be tied around the leg 
with handkerchiefs ;, and pads may be made of hay or 
moss. It should be possible to move the person without 
causing any severe pain. 

Freezing. — An effort should be made to restore the 
frozen parts by rubbing with cold water or snow until the 
white color disappears. Heat should not be applied at 
first. If the whole body has been exposed to severe cold 
until there is danger that it is injured, it should be rubbed 
thoroughly with snow or cloths wet in cold water, until the 
circulation has been well established. Heat should not 
be applied at first, and only gradually afterward. 

Hysterics. — Sometimes after excessive laughing or cry- 
ing a person may have what resembles a severe convulsion. 
AVe call such an attack hysterics. In most cases the at- 
tack will pass off quickly if the person is left alone. Too 
much attention and sympathy only aggravate the trouble. 

Jarring the Brain. — Children often become stunned by 
a blow or a fall. This is the result of shaking or jarring 
the brain. Have the child remain as quiet as possible, 
and in a short time recovery will be complete. If, how- 
ever, this is not the case, a physician should be called. 

Pain. — As a relief from pain, the mustard plaster is in 
common use. It is made by mixing an equal quantity of 
ground mustard and flour, adding sufficient water to make 
this into a paste ; the white of an egg is even better than 
water. Spread this paste upon a cloth and lay it over the 
painful part. If the skin is very sensitive, some thin mate- 
rial may be placed between the plaster and the body. The 



278 THE ESSENTIALS OF HEALTH 

plaster should remain long enough to redden the skin, but 
not long enough to produce a blister. 

Poisons. — Many persons are very careless with the 
drugs and chemicals they have about the house. They 
keep bottles and packages of all kinds on one shelf, whether 
they contain poison or not. This certainly should not 
be done. All bottles and packages should be carefully 
labeled, and moreover the poisons should be kept in a 
place by themselves. Indeed, every bottle or package 
containing a poison ought to have the word "POISON" 
upon it in large letters, and should be placed on a shelf 
out of easy reach, or, better still, be kept under lock and 
key. It is a wise thing to tie a paper cap over the cork 
of any bottle containing poison ; then the presence of this 
paper and the necessity of removing it will serve as a re- 
minder of what the bottle contains. It is never wise to 
pick up a bottle and quickly take a dose from it ; first look 
at the label, and make sure you know what you are taking. 

The first thing one should do in every case of poisoning 
is to try to find out what poison has been taken. Often 
the label of the bottle or package from which the dose has 
been taken will give the information, or the person who 
has taken the poison may be able to tell. In all cases, 
send some one for a physician while you are treating the 
case as best you can. 

In treating cases of poisoning, an emetic is sometimes 
necessary. A tablespoonful of powdered mustard mixed in 
a glass full of clear water is a common emetic. The dose 
should be repeated every ten minutes until vomiting oc- 
curs. If the mustard is not at hand, try the same quantity 
of common salt. After taking these remedies, the vomit- 
ing may be hastened by thrusting the finger into the mouth 
until it touches the back of the throat. 



EMERGENCIES 279 

The following- are a few of the more common poisons 
with their antidotes : — 

For muriatic, nitric, and sulphuric acids : Give three or 
four teaspoonfuls of baking soda or magnesia, or chalk or 
saleratus, dissolved in a glass of water. In an hour follow 
this with some soothing drink, as flaxseed tea. Do not 
give an emetic. 

For carbolic acid or creosote : Give the white of several 
eggs. Give quantities of milk. Do not give an emetic. 

For ammonia, solutions of potash, or soda, or lye : Give 
vinegar or lemon juice. Follow this with cream. Do not 
give emetics. 

For nitrate of silver or lunar caustic : Drink half a 
glass of warm water in which a teaspoonful of ordinary- 
salt has been dissolved. Use no emetic. 

For corrosive sublimate and other preparations of mer- 
cury : Give the white of eggs. Use no emetics. 

For preparations of copper, as verdigris, blue vitriol, and 
poisoning from eating food which has been cooked in cop- 
per vessels : Give the white of eggs. Use no emetics. 

For copperas or green vitriol : Give a cup of water, in 
which has been dissolved a teaspoonful of ordinary baking 
soda. Later give raw eggs in milk. Use no emetics. 

For arsenic, Fowler's Solution, paris green, or rough on 
rats : Cause repeated vomiting. Procure from the near- 
est druggist some freshly made hydrated sesquioxicle of 
iron, and give two or three tablespoonfuls, in half a glass 
of water, every fifteen or twenty minutes, until four or 
five doses have been given. 

For opium, morphine, laudanum, paregoric, soothing 
sirups, and all mixtures which produce sleep : Cause re- 
peated vomiting. Give very strong coffee, without sugar 
or milk, freely. Keep the patient awake until the physi- 



280 



THE ESSENTIALS OF HEALTH 



cian arrives, by walking or any other form of exercise, 
resorting to whipping, if necessary. 

Poisonous Plants. — There are a few berries and plants 
that act as severe poisons when taken into the system. 
Among these might be mentioned henbane, poison parsley, 
indian tobacco, poison elder, wild parsnips, deadly night- 
shade, and the cardinal flower. The only safe way to 
escape poisoning is to avoid eating any plant or berry 
unless you know what it is. The treatment is to give 
emetics until there is free vomiting, after which strong hot 
coffee may be given for its stimulating effect. 



Fig. 112. 



Fig. 113. 




Fig. 112. — Virginia creeper. 

Fig. 113. — Poison ivy, sometimes mistaken for the Virginia creeper, 
poison-ivy leaf has three leaflets, and the Virginia creeper five. 



The 



Poison ivy (see Figs. 112, 113), poison oak, and poison 
sumac cause a painful rash, even if they but lightly touch 
the skin. Indeed, it is not necessary that there be actual 
contact, as the near presence of some of these plants may 
be all that is necessary to cause poisoning. Bathe the 



emergencies 



281 



skin frequently with a strong solution of ordinary baking 

soda. Covering the skin with vaseline is also useful. 

The best treatment for poisoning from poison ivy is the 
local application of grindelia robusta. Procure one ounce 
of the tincture at any drug store, and mix it with ten 
ounces of water. Apply cloths moistened in this solution 
to the poisoned surface. 

Poisoning also occurs from eating tainted meat, cheese, 
or ice cream, and from mistaking toadstools for mush- 
rooms. In all these cases, 
give an emetic, unless vomit- 
ing has already occurred, and 
later give plenty of strong 
coffee. 

Some Ways of carrying an 
Injured Person. — The easiest 
way to carry a person of about 
your own size, should it be 
necessary to do so without as- 
sistance, is upon the back, in 
the way the boy in Fig. 114 
is carrying his friend. 

If the person loses con- 
sciousness, or feels faint 
from the effects of the injury, 
it is best to get a blind, or 
door, or some similar flat sur- 
face, and lay the person care- 
fully on it, by gently sliding him from the ground. When 
the destination is reached, leave the person upon this 
temporary stretcher until the surgeon arrives. 

Sprains. — Place the injured joint in the position which 
is the most comfortable. Apply cloths wrung from hot 




Fig. 114. — Carrying a boy who has 
injured one of his legs. 



282 THE ESSENTIALS OF HEALTH 

water about the joint, changing the cloths frequently, in 
order that the heat may be as great as can be endured. 
Continue these hot applications for at least half an hour. 
Then continue the applications with water that is not so 
hot. A surgeon should always be consulted. 

Stings. — The stinger of wasps, bees, and other insects 
often remains within the wound. This should be removed 
with the fingers or with small forceps. Apply a strong 
solution of ordinary soda to the wound. Boys know very 
well that an application of mud gives prompt relief. 

Suffocation from Gas. — When a person is discovered 
suffocating from inhaling gas, the first effort must be to 
revive respiration. If his breathing is very faint, or if it 
should cease altogether, perform artificial respiration as 
described for drowning, at the same time placing hot 
water bags or bottles around the body. As soon as he is able 
to swallow, give strong hot coffee as a stimulant. Keep 
in mind the fact that the person who has been breath- 
ing this bad air is suffering from want of oxygen. Place 
him where he can obtain all the fresh air possible. 

Sunstroke. — Remove the person suffering from sun- 
stroke to a cool place, and apply bags of cracked ice on 
or around the head. A method highly recommended is 
to remove all the clothing and pour cold water over the 
entire body. An ordinary watering pot may be held three 
or four feet above the body, and the water poured first 
upon the head, then on the chest and abdomen, and lastly 
on the extremities. 

Occasionally persons are affected by the heat in such a 
way that they are very pale, the pulse is weak, and the 
skin cool. In these cases, the treatment should consist 
in applying warmth externally, and giving warm drinks 
internally. Such cases are often rapidly fatal. 



CHAPTER XXXI 
THE EMERGENCY NURSE 

It often happens when some member of the family is 
taken suddenly ill, that one of the older children is called 
on to take the place of a nurse. Some children, even 
when very young, seem to have a natural ability for this 
work. There are many things which an inexperienced 
nurse can do as well as one more experienced : such as 
bathing the hands and face, brushing the hair, moistening 
the lips, cleaning the nails — mere trifles in themselves, 
yet they give comfort and cheer to the patient, and con- 
tribute in no small degree to his recovery. A few simple 
directions may increase the usefulness of the young emer- 
gency nurse. 

General Suggestions. — A pleasant and cheerful coun- 
tenance is sometimes the best kind of medicine for the 
sick. If you cannot take joy, hope, and good cheer into 
the sick room, you had better stay away. It is always 
well to take sunshine with you wherever you go, but it is 
especially important to take it with you when you enter 
the sick room. 

Sleep. — It may be stated as a general rule, that a sick 
person should never be awakened when quietly sleeping. 
Unless the physician has given orders to the contrary, it is 
to be understood that the patient is never to be awakened 
to take medicine. Sleep is necessary to health, as we all 
know ; it is even doubly necessary for those who are ill. 

283 



284 THE ESSENTIALS OF HEALTH 

Cleanliness. — Cleanliness is a very important item in 
the recovery of the sick. A sponge bath is always re- 
freshing, and is an aid to recovery, if given in a way that 
does not tire the patient. If he is without fever and the 
body is cool, the water for bathing should be about the 
temperature of the body. If there is fever, the water 
should be cool. 

Food. — There are a few foods which can be given to 
almost any sick person without danger, and with benefit. 
Milk is the most important of these. When there is fever, 
it should be given cold, a few swallows at a time. If a 
person is weak, and the body cold, warm milk may be 
sipped with great benefit. When milk is heated, it may 
be brought just to the boiling point, but should never be 
allowed to boil. 

Fresh Air. — There should always be an abundance of 
fresh air in the sick room. Fresh air is necessary in 
health and becomes far more necessary in sickness. 
Therefore, see that the room is well ventilated at all times. 
Do not allow currents of air to blow directly upon the 
sick one, but prevent this by means of a screen, or an 
improvised shield made by throwing a blanket over a 
couple of chairs. Remember that even when a room is 
very cold, it may be filled with impure air; the tempera- 
ture of the air has nothing to do with its purity. 

A Well-lighted Room. — The nurse should ahvays see 
that the room is properly lighted. Some persons appear 
to think that the sick room should be kept very dark. 
Light is essential to all who are well, and much more essen- 
tial to those who are ill. Occasionally, to be sure, it may 
be necessary to have the room darkened in treating some 
eye trouble, but this should be done only when the physi- 
cian has given strict orders to that effect. The room 



THE EMERGENCY NURSE 285 

should be so located that at some time during the day the 
sun shines directly into it. Even if the patient is suffering 
from a severe headache, and the strong light is very pain- 
ful, it is better to shade the eyes and allow the sunlight to 
enter, than it is to keep the room dark all through the 
day. 

Temperature. — It is essential to the patient's comfort 
that the temperature of the room should be right. If 
there is no fever, and if the person is inclined to be cool, 
the coverings should be warm, and there should be some 
heat in the room. If the person is feverish, the coverings 
should be light, and the room should be kept cooler. 



CHAPTER XXXII 
CONTAGIOUS DISEASES 

Bacteria. — Bacteria are also known as germs and mi- 
crobes. They are living bodies, so minute that the high- 
est powers of the microscope are necessary in order to see 
them. So minute are they that millions of them, we 
are told, would not occupy a space larger than a small 
drop of water. The rapidity of their growth is- almost 
incredible. If a few germs are placed in a solution 
favorable to their growth, such as milk or beef tea, 
countless millions of them will develop within a few 
hours. 

The Destruction of Bacteria. — Bacteria may be destroyed 
by chemical agents that are known as disinfectants. 
They are also destroyed by the application of heat, for 
by raising the temperature to the boiling point nearly all 
forms of germ life may be destroyed. A few species of 
bacteria are not killed unless the boiling point is main- 
tained from fifteen minutes to half an hour. 

Some Bacteria are Useful. — All forms of decay are 
produced by bacteria. If meat or fruit or any other 
organic matter is left exposed to the air, it will sooner 
or later break down and soften ; after a time it may dis- 
appear altogether from view. This is entirely the work 
of these minute organisms. In the course of this soften- 
ing process the organic matter not only is broken down, 
but also undergoes chemical change. After being acted 

286 



CONTAGIOUS DISEASES 287 

upon in this way the matter is in a condition to be taken 
up readily by plants as food. 

Thus bacteria accomplish an immense amount of valu- 
able work ; for they not only remove dead organic matter 
from view, but they also prepare this matter to become 
useful again as food for plant life. 

Bacteria also cause Disease. — There are a number of 
diseases now known to be caused by germs. Among the 
diseases which physicians know, or fully believe to be 
caused by germs, we might mention consumption, pneu- 
monia, diphtheria, typhoid fever, smallpox, yellow fever, 
cerebrospinal meningitis, scarlet fever, measles, whooping 
cough, chicken pox, lockjaw, dysentery, and influenza. 

Modes of spreading Disease. — It is easy to understand 
how readily these minute germs may be carried from one 
person to another, from one house to another, or even 
from one village to another. It is certainly very easy to 
see how one of these germ diseases might be contracted 
by a pupil who handles the books or pencils that had been 
used by one who was ill with such a disease. 

Every pupil should be provided with his own pencil 
and paper, books, and drinking cup. When books are 
furnished the pupils, it is wise to require each pupil to 
cover his books with a good manila paper, which can be 
removed and burned at the close of the year, or as soon 
as the pupil is through with the books. 

It is probably true that ordinary hard colds are due to 
germs. Therefore, persons with colds should be very 
careful about the use of handkerchiefs. Handkerchiefs 
should be frequently changed and the soiled one thrown 
immediately into boiling water, or placed temporarily in 
a paper bag which can be burned when the handkerchiefs 
are removed. 



288 THE ESSENTIALS OF HEALTH 

One agent in spreading contagious diseases is the dust 
which rises from the floors upon which expectorated matter 
has been deposited. The almost universal custom among 
men of expectorating upon sidewalks is most pernicious. 
Laws have been enacted in nearly all of our cities against 
this habit, and it is to be hoped that they will be enforced. 

Still another source of danger comes from insects. It 
was positively proved during the Spanish-American war 
that typhoid fever was carried from camp to camp by 
means of flies. It has also been proved that yellow fever 
is transmitted from one person to another through the 
bite of a certain species of mosquito. When the mosquito 
bites one who is ill with this disease, it receives some of 
the disease germs within itself. Then when it bites a 
healthy person it transmits these germs to his blood. If 
the body is not in a strong, healthy condition, and so able 
to withstand the disease germs, the disease may develop 
as a result of the mosquito bite. 

Protection of the Body. — The body is well protected 
from the action of the germs of disease ; otherwise it 
would be difficult to understand how any of us escape 
being ill all the time. The outer covering of the skin is, 
in health, a great protection. The mucous membranes 
which line the respiratory and alimentary tracts also 
protect the body. While this protection may not be 
complete, even when these membranes are in a perfectly 
healthy condition, } r et it is true that any break in their 
surface greatly favors the entrance of these germs. 
- Another means of protection resides within the body 
itself. Indeed, it might well be stated that the body is 
constantly fighting the germs of disease. This power of 
resisting disease is often called the resistive power of the 
body. It is believed to reside largely in the white corpus- 



CONTAGIOUS DISEASES 289 

cles of the blood. These minute bodies have the power 
to destroy a limited number of germs, and they are there- 
fore a great source of protection to the body. 

It is also probably true that there always exists within 
the body, when in a perfectly healthy state, an antidote 
which is protective against the action of man)^ of the 
poisonous germs. This antidote is known as an antitoxin. 
It is without doubt a great aid in protecting us from seri- 
ous disease, acting in a manner somewhat similar to the 
antitoxin of diphtheria. 

The " Toxins " of Bacteria. — When bacteria are placed 
in a medium favorable to their growth and development, 
they are capable of producing or manufacturing a " toxin " 
or poison. To illustrate : The germs of diphtheria would 
not produce such disastrous results if they only rested 
upon the membranes of the throat, and did not manufac- 
ture any poison. Indeed, it has been proved that the 
germs of diphtheria are in the throats of many healthy 
children who escape having the disease. In order to 
cause diphtheria, the germs must become active and pro- 
duce their poison. When such a poison is produced, it is 
quickly absorbed into the blood, acting as a poison to the 
whole system. The danger from diphtheria, therefore, is 
from the toxin or poison produced by the germs of 
diphtheria. 

The Antitoxin of Diphtheria. — As we have antidotes 
for many kinds of poison, so we have an antidote for the 
toxin or poison of diphtheria, called antitoxin. This is a 
preparation especially made to counteract the poisons of 
this disease, which have been absorbed into the blood. It 
destroys the power of these poisons, and if administered 
in time will, in nearly every case, prevent a fatal termina- 
tion of the disease. 



290 THE ESSENTIALS OF HEALTH 

Consumption. — Consumption, more accurately called 
tuberculosis, is now known to be due to a germ called the 
tubercle bacillus. The sputum or expectorated matter of 
consumptive persons is filled with these germs. When 
the sputum dries it is easily powdered, forming a part of 
the atmospheric dust. This dust is inhaled by people, 
and if a person is not in good health, the germs may find 
a suitable soil in which to grow and produce the disease. 

All persons who have consumption should be under the 
watchful care of a skilled physician, and his directions 
should be carefully carried out. He will certainly order 
that every effort be made to destroy all expectorated mat- 
ter as soon as possible, and that under no circumstances 
should it be allowed to become dry. Small pieces of 
cloth or little paper cups should be carried, and when 
these have been used they should be burned at the first 
opportunity. If a china cup or cuspidor is used, it must 
be partially filled with water, and should be frequently 
emptied, and after emptying washed with boiling water. 

Pneumonia. — Pneumonia is an inflammation of the 
lungs, caused by a distinct germ. The germs are found 
in the sputum of the person who has the disease. These 
germs are found also in the mouth and throat of persons 
who are apparently in the best of health, and who escape 
having the disease. This may be due to the fact that the 
breathing apparatus is so healthy that the germs do not 
find a suitable place in which to grow ; or it may be due 
to the action of the white corpuscles or to the natural 
antitoxin of the body. 

Influenza. — There is every reason to believe that influ- 
enza, also, is due to a germ, which is inhaled in the air ; 
therefore, discharges from the nose and throat of a person 
who has influenza should be promptly destroyed. 



CONTAGIOUS DISEASES 291 

Diphtheria. — The germs of diphtheria are very active, 
and the most stringent measures are necessary in order to 
prevent and restrict the disease. All discharges from the 
nose, mouth, and throat should be destroyed at once, as 
they probably contain immense numbers of these virulent 
germs. The patient should be placed in a well-lighted 
room in which there is little furniture, and no one should 
be allowed to enter it but the physician and nurse. If 
there is diphtheria in the neighborhood, village, or city, a 
physician should be consulted without delay whenever 
there is any soreness of the throat. This is a wise precau- 
tion, for it frequently happens that what appears at first 
to be a simple sore throat may prove to be a serious form 
of diphtheria. 

Typhoid Fever. — Typhoid fever is usually caused by 
drinking water in which there are germs of the disease. 
Sometimes it is produced by milk made impure by wash- 
ing the milk cans with water which contains the typhoid 
fever germs. Milk is also sometimes adulterated with 
such water. Ordinary filters will not remove these germs 
from the water. When filtering is properly done on a 
large scale, as in city water works, the purifying of the 
water can be accomplished in a very satisfactory manner. 
Water can also be made free from these germs by boiling. 
Typhoid fever is now called an unnecessary disease ; that 
is, no one need have this disease if only the water supply 
is pure. Here is another reason why the question of 
water supply is so very important. 

Scarlet Fever. — A germ probably causes scarlet fever 
also. The person who is ill should be placed in a well- 
lighted room, and no one should be allowed to enter it 
but the doctor and nurse. All discharges from the nose, 
mouth, and throat should be immediately destroyed. 



292 THE ESSENTIALS OF HEALTH 

Later, when the body is " peeling," special care is neces- 
sary in order to destroy the minute scales, thus preventing 
their becoming a part of the dust of the atmosphere, and 
a possible source of contagion to others. When a person 
has been exposed to scarlet fever, the disease may show 
itself in a very short time. It generally appears in less 
than seven clays after exposure, quite frequently in only 
two or three days, and sometimes in only a few hours. 

Measles. — Measles is probably a germ disease. It is 
easily spread among children ; hence the same precautions 
should be taken as for other contagious diseases, in order to 
prevent its spread. After exposure to measles, it is usually 
from ten to fourteen days before the disease develops. 

Whooping Cough. — As whooping cough is a disease 
which is easily communicated from child to child, great 
care should be taken that the one who has it does not 
mingle with other children, and thus expose them. 

Smallpox. — Smallpox is spread by means of the par- 
ticles which come from the surface of the patient's body. 
As vaccination is a protection against contracting the 
disease, no one should neglect this precaution. It is best 
to be vaccinated at least once every five years, for one vac- 
cination does not necessarily protect for life. When small- 
pox is prevalent, a person should be revaccinated, without 
regard to the length of time since the last vaccination. 
When the germs of smallpox have entered the system, it 
is usually ten days to two weeks before the disease mani- 
fests itself. 

Isolation. — The word " isolation" means " to place by 
itself," or "to separate from others." But this does not 
mean that a person who is to be " isolated " must be placed 
alone in a room and neglected. It does mean, however, 
that every precaution is taken in order that no one shall 



CONTAGIOUS DISEASES 293 

come near the patient except the nurse and the physician. 
The fact that a person lias a light case of some contagious 
disease does not lessen the necessity of isolation ; when 
communicated to another person the disease might be so 
severe as to prove fatal. 

When the attendant leaves the sick room, the outer 
clothing should be changed, and the face, hands, and hair 
thoroughly washed. If there are several children in the 
house, and one of them is taken ill with diphtheria or scar- 
let fever, the children who are well should not be allowed to 
attend school or to mingle in any way with other children, 
until all clanger of their conveying the disease is past. 

Disinfection in the Sick Room. — A disinfectant is an 
agent that destroys disease germs. The simplest and one 
of the best disinfectants is heat. Boiling for half an hour 
is sufficient to destroy nearly all germ life. All cups, 
spoons, and vessels of every description used about the 
sick room should be placed in water before being taken 
from the room, and then should be thoroughly boiled. 
All clothing and bedding which will not be injured thereby, 
should be treated to the boiling also. The modern method 
of disinfecting with steam under pressure is very effective, 
and is used in many cities. It requires a plant constructed 
for that purpose. 

Among the chemical agents which are marked disinfec- 
tants might be mentioned bichloride of mercury or corro- 
sive sublimate, formic acid or formaldehyde, and carbolic 
acid. These are most powerful disinfectants, but they 
are also very powerful poisons. Heat is so good and so 
safe a disinfectant that it can be made to meet all ordi- 
nary needs. 

After the removal of the sick person from the room, 
everything should be thoroughly disinfected. If the bed- 



294 THE ESSENTIALS OF HEALTH 

ding, garments, and furniture are not too valuable, they 
would better be burned, or whenever possible they should 
be boiled for at least half an hour. The following method 
of disinfecting a room is a good one to adopt when the 
contents of the room cannot be burned. Spread all 
clothing and bedding loosely over the chairs. With 
pieces of cloth or cotton tightly close every opening about 
the room so far as it is possible, pasting strips of -paper 
along the sides of the windows and doors. In order to 
prevent any danger from fire, take an ordinary washtub 
and in it place water to the depth of a couple of inches. 
Set a shallow iron pan or a low iron kettle upon a couple 
of bricks in the center of the water. For a room ten feet 
square, use three pounds of sulphur. Break the sulphur 
into small pieces and moisten them slightly with alcohol. 
Put the sulphur in the iron dish and set it on fire, using 
care not to breathe the strong fumes which will immedi- 
ately arise. Promptly leave the room and close the door 
tightly. After twenty-four hours throw open the doors 
and windows and allow the gas to escape. Wash all the 
woodwork with soap and water, and if possible have the 
room newly papered and painted. It is wise to allow the 
contents of the room to be exposed to the outdoor air for 
a day or two after the disinfecting, if the weather will 
permit. 

If one is living in a place where there is a Board of 
Health, it is always better to notify one of its members 
when a room needs to be disinfected. 



INDEX 



Abdominal cavity, 41 

Absorption, 62-70 ; definition of, 62 ; 
from the large intestine, 64-65 ; 
from the small intestine, 64 ; 
from the stomach, 62 

Accidents. See Emergencies 

Acids, in milk, 16-17 

Action, reflex, 206-207; and the 
spinal cord, 204-207 ; course of 
nerve current in, 205-206 ; im- 
portance of, 206 

"Adam's apple," 97 

Adenoids, 96 

Adipose tissue, 162 

Air, abundance of, necessary, 110- 
112; amount inhaled, 103, 108; 
for the sick, 264; nature of ex- 
pired, 104; inspired, 103-104; in 
the lungs, 100-104; necessity for 
pure, 110 

Air cells, 98-99 

Albumen, a proteid, 15 ; in eggs, 19 ; 
in milk, 16 

Alcohol, causes of craving for, 34-35, 
36, 38, 59-60 ; in beer, 35-37 ; in 
cider, 33-35; in distilled liquors, 
37-38 ; in wine, 35 

Alcohol, deceptions of, 254; effects 
of, on brain, 215, 254 ; on cells, 
6-7 ; on circulation and heart, 
90-92, 254; on control of body, 
255 ; on kidneys, 121 ; on liver, 
60-61; on lungs, 104-105; on 
mind, 255 ; on mucous mem- 
brane, 92; on muscular system, 
150-151, 158-160; on nervous 
system, 212-216, 254-255; on 
stomach, 59-60 ; on temperature 
of the body, 185-186 

Alcoholic drinks, 32-38 ; beer, 35-36 ; 
cider, 33-35; distilled liquors, 
37-38 ; wine, 35 ; harmful effects 
of, 34, 35 ; narcotic power of, 255 ; 
social dangers of, 255 



Alimentary canal, 41 

Amoeba, 4-5 

Amoeboid movements, 4 

Animal foods, 9, 10, 13-14 

Animal heat, 180-186; and body 

temperature, 181-186; effects of 

alcohol on, 185-186; sources 

of, 180-181 
Animal matter, in bones, 123 
Animals, bites of, 265 ; teeth of, 42 
Antidotes to poisons, 279 
Antitoxin, of diphtheria, 289 
Aorta, 80, 86 
Appendicitis, 41-42 
Appendix, vermiform, 41 
Arms, bones of, 136 
Arterial blood. See Blood 
Arteries, and the pulse, 85-86 ; 

bleeding from, 267 ; described, 

86-88 
Atlas, of spinal column, 134 
Auditory canal, 233-234 
Auditory nerve, 236 
Auricles, of the heart, 80 
Axis, of spinal column, 134 



Bacteria, 32-33 ; destruction of, 
286; some useful, 286-287; that 
cause disease, 287 ; toxins of, 289 

Ball-and-socket joint, 140 

Bathing, 173-177 

Beat, of the heart, 82-84 

Beer, alcohol in, 36, 37 ; harmful 
effects of, 37 ; how made, 35-37 

Biceps muscle, 152 

Bicuspid teeth, 45 

Bicycle, for exercise, 156 

Bile, amount secreted by the liver, 56 ; 
as a laxative, 58 ; importance of, 
to digestion, 56-57 ; passage of, 
to the intestines, 56 

Bites, from animals, 265 

Bladder, 120; gall, 56 



295 



296 



INDEX 



Bleeding, how to control, 265-270; 
stopped by coagulation, 75-77 

Blindness, color, 222 

Blind spot, 221-222 

Blood, the, 71-77 ; and the cells, 5, 6 ; 
and the lymph, 66, 67 ; arterial, 
74, 75; 'circulation of, 78-93; 
coagulation of, 75-77 ; corpuscles 
of, 72-73; course of, 81-82; 
distribution of, 71 ; venous, 74, 75 

Blood vessels, and coagulation, 75- 
76 ; controlled by vaso-motor cen- 
ter, 203-204; effects of alcohol 
on, 91-92, 254; of the bones, 123; 
of the brain, 191 ; of the lungs, 99 ; 
of the muscles, 143 ; of the skin, 
162; of the small intestine, 64; 
of the teeth, 44 

Boards of Health, 117-118 

Body, human, and foods, 8-14, 15 ; 
and mind, 201 ; bathing of, 173 ; 
cells of, 1-7 ; changes in, 2-3 ; 
composition of, 6 ; growth and 
development of, 8, 154; health 
of, important to mental power, 
155-156 : importance of a healthy, 
1, 154-156, 209, 253; protection 
of, against disease, 288-289 ; 
success dependent upon, 1, 262 ; 
surface of, 3 ; temperature of, 
180-186 ; waste of, 3, 8, 39 

Bone, cells of, 3 ; importance of 
minerals in forming, 16 

Bones, 122-129 ; animal and min- 
eral matter in, 123-125 ; broken, 
125 ; changes in, 126 ; general 
description of, 122 ; injured by 
careless position, 125-129 ; mar- 
row, 123 ; membrane of, 122 ; 
of arms, 136; of feet, 138; of 
legs, 137-138 ; of middle ear, 235 ; 
of pelvis, 136-137; of skull, 
130-132; of spinal column, 132- 
134; tissues of, 122-123; tur- 
binated, 230 

Bowels, importance of action of, 
69-70 

Brain, anatomy of, 191-196 ; care 
of, 209-212;' divisions of, 201; 
functions of, 201-204; jarring of, 
257; localization of, 200-201 



Bread, preparing of, 26 
Breast bone, or sternum, 135 
Breathing, and exercise, 158; and 
health, 94; mouth, 96; through 
nose, 95. See also Respiration 
Bronchi, 98-99 
Bruises, treatment of, 270 
Buccinator muscle, 151 
Burns, treatment of, 270-271 



Cancellous tissue, in bones, 122-123 

Canine teeth, 44, 45 . 

Capillaries, bleeding from, 267 ; 

of blood vessels, 65, 81, 88; of 

lymph vessels, 65 
Carbon, 9 
Carbon dioxide, and respiration, 94; 

a poison, 108-109 ; in water, 12 
Cardiac portion of the stomach, 51 
Carrying the injured, 281 
Cartilage, cells of, 3; of spinal 

column, 133 
Casein, 15, 16, 54 
Catarrh, gastric, 59 ; of nose and 

throat, 96 
Cavities, abdominal, 41 ; nasal, 95 ; 

of the heart, 79-80; thoracic, 

99, 101, 135 
Cells, air, 98-99 ; body and the blood, 

5 ; body composed of, 2 ; building, 

33 ; description of, 2 ; destructive, 

32-33 ; division of, 4 ; effect of 

alcohol on, 6-7 ; function of, 5 ; 

growth and development of, 3-4; 

membrane of, 7 ; motion of, 4-5 ; 

nerve, 189-190; nourishment of, 

65-66 ; of gastric glands, 52, 53 ; 

of the liver, 56; of plants, 32; 

of secretory glands, 39 ; yeast, 

33, 34, 35 
Cellulose, 69 
Cement, in teeth, 45 
Centers, nerve. See Nerve 
Cereals as food, 20-21 ; proteids 

in, 16, 19 
Cerebellum, 196; function of, 201 
Cerebro-spinal system, 187 
Cerebrum, 192-194; and the mind, 

200; function of, 199-200; gray 

and white matter of, 193-194 



INDEX 



297 



Character, and control of the body, 

256, 257 
Chest or thorax, a tight box. 101 ; 

in respiration, L 02-103 ; position 

of lungs in, 99 ; sounds of, 103-104 

Chewing. See Mastication 

Chloroform, effect of, on cells, 7 

Choroid, 220 

Chyle, 58, 66 

Chyme, 54 

Cider, alcohol in, 34-35 ; harmful 
effects of, 34 

Cigarette smoking, a foe to national 
vigor, 244 ; begun through imita- 
tion, 248-249; effects of, on am- 
bition, 257 ; on brain, 250 ; on eyes, 
248 ; on growth, 249, 251 ; on 
mental ability, 252, 257, 258 ; on 
moral natures, 250 ; on muscles, 
249 ; on nasal passages, 249 ; on 
success, 249, 251 ; on working 
power, 249, 250, 252; how first 
introduced, 244; how user's desire 
increases, 246 

Cigarettes, harmful effects of, 93; 
most dangerous form of tobacco, 
245 

Circulation of blood, 78-93 ; aids 
to, 90; course of, 81-82; effects 
of alcohol on, 90-92, 254 ; effects 
of tobacco on, 92-93 ; rapidity of, 
89-90 

Circulation, of food, 12; of lymph, 
66-67 

Clavicle, 136 

Cleanliness, importance of, to health, 
17-19, 30, 173-177, 284 

Clothing, 177-179 

Clotting of blood. See Coagulation 

Coagulation, of blood, 75-77 

Colds, treatment for, 179 

Color, of the skin, 164-165 

Color blindness, 222 

Column, spinal. See Spinal 

Common sensation, 242 

Compact tissue, in bones, 122-123 

Conjunctiva, 216-217 

Constipation, seriousness of, 69 ; sim- 
ple remedies for, 70 

Consumption, and spitting, 49 ; pre- 
cautions against, 287-288 



Contagious diseases. Sec 1 J)i 

Contractions, of the heart, 80 81, 
83-84; of the intestine, 58 59 • 
of the muscles, 145-147; of the 
stomach, 54 

Control of the body, effects of alco- 
hol on, 254, 255; importance of, 
253 

Convolutions, of the brain, 192 

Convulsions, treatment of, 271 

Cooking, proper methods of, 28-29 

Cord, spinal. See Spinal 

Corn, as a food, 21 

Cornea, 220 

Corpuscles, blood, 71-73 ; lvmph, 67; 
red, 72-73; white, 72," 288-289 ; 
touch, 239 

Cotton, for clothing, 178 

Cranial cavity, 191 ; nerves, 194- 
196 

Current, nerve, 199 ; course of, 
205-206 

Cuticle, 162 

Dairies, importance of cleanliness 
in, 17-19 

Decay. See Decomposition 

Decomposition, and fermentation, 33 ; 
in bread-making, 26 ; of organic 
matter in water, 13 ; of plants, 
32-33 

Deglutition. See Swallowing 

Deltoid muscle, 152 

Dentine, 45 

Deodorizers, 115 

Dermis, 162-165 

Development of cells, 3-4 ; of mus- 
cles, 154 

Dextrin, 24 

Diaphragm, a muscle, 152 ; in 
breathing, 94, 101, 102, 103 

Digestibility of foods, 55 

Digestion, 39-50 ; and energy, 9, 10, 
29 ; and exercise, 27-28 ; con- 
ditions affecting, 54-56 ; effects 
of alcohol and tobacco on, 59-61 
in stomach and intestines, 51-61 
intestinal juices in, 39, 52-54, 59 
liver in, 56-58 ; mastication and, 
42; object of, 39; of cereals 
21, 55; of eggs, 19, 55; of fats 



298 



INDEX 



23, 55 ; of fruits, 22, 55 ; of meats, 
20, 55; of milk, 17, 55; of pro- 
teids, 53-54, 57, 58 ; of starchy 
foods, 25, 55, pancreas in, 58 

Digestive juices, 39, 42 

Diphtheria, antitoxin of, 289 ; treat- 
ment of, 291 

Diseases, contagious, 117, 286-294; 
modes of spreading, 287-288 ; 
protection against, 288-289 

Diseases of the skin, 168-170 

Disinfectants, 115, 273-274 

Disinfection, 293-294 

Dislocations, 271 

Distilled liquors. See Liquors 

Drowning, reviving from, 271-273 

Ducts, bile, 56 ; sweat, 165 ; tho- 
racic, 65 

Dust, and the spread of disease, 
288 

Dusting, proper method of, 116 

Ear, care of, 237 ; external, 233-234 ; 

foreign bodies in, 238 ; internal, 

236; middle, 234-236 
Eating, harmful effects of improper, 

28, 31 
Economy, in food, 30 
Eggs, as food, 15, 19; constituents 

of, 19 
Elasticity, 12 
Elements, food, 9 
Emergencies, 265-282 
Emergency nurse, 283-285 
Emetics, in poisoning, 278 
Emulsion, 58 
Enamel, of teeth, 45 
Energy, 8-10 ; sunlight and, 9 
Epidermis, 162-165 ; changes in, 

164; uses of, 164 
Epiglottis, 50, 98 

Equilibrium, how maintained, 237 
Erect position, importance of, 126- 

129 
Eustachian tube, 49, 236 
Excretions, 39 
Excretory organs, 39, 161 
Exercise, 154-160; amount of, 155- 

156 ; and bodily temperature, 183 ; 

and the mind, 209, 210; benefits 

of, 157-158 ; necessity for, 154 



Expiration, 101-103 

Extensor muscles, 148 

Extremities, bleeding from, 267-269 ; 
lower, 137-138; upper, 136 

Eyes, blind spot in, 221-223 ; care 
of, 223-225 ; defects of, 222-223 ; 
foreign bodies in, 274-275 ; func- 
tions of parts of, 221 ; protec- 
tion for, 217-219 

Fainting, 273-274 

Farsightedness, 222-223 

Fats, absorption of, 64 ; digestion 
of, 53-54 ; excess of, 24 ; impor- 
tance of, 23 ; in cereals, 20, 21 ; 
in eggs, 19 ; in meat, 23 ; in milk, 
16 ; in the body, 6 

Femur, 137 

Fermentation, a form of decompo- 
sition, 33 ; in beer, 35—37 ; in 
bread-making, 26 ; in cider, 33-35 ; 
in distilled liquors, 37 ; in wine, 35 ; 
work accomplished by, 33 ; yeast 
in, 33-36 

Fever, 184; scarlet, 291-292; ty- 
phoid, 13, 291 

Fibers, muscle, 143; nerve, 190-191; 
of the spinal cord, 197 

Fibrin, 76-77 

Fibula, 137 

Finger nails, 3, 172 

Flexor muscles, 148 

Flies, and the spread of disease, 
288 

Fluids, of the body, 6 ; proteids 
in, 15 ; lachrymal, 219 

Follicle, hair, 170 

Foods, absorption of, 62-70 ; amount 
and kind required, 27-28 ; a 
source of energy, 27 ; source of 
heat, 180; building and repair- 
ing, 14 ; care of, 19 ; classifi- 
cation of, 10-11; cooking of, 
28-29; definition of, 10; diges- 
tion of, 39, 42, 48, 51-61; 
economy in, 30 ; elements of, 9 ; 
for the sick, 284; fuel, 14; inor- 
ganic, 11, 13; nitrogenous, 15-22; 
non-nitrogenous, 23-31 ; organic, 
13-14; tissue-building, 5; water 
and, 12 



INDEX 



299 



Force. See Energy • 

Foreign bodies, in ear, 27 1 ; in 

eye, 27 1 27."); in nose, 275-276; 
in throat, 276 

Fractures, 276 

Freezing, 183-184, 277 

Frontal bone, 132 

Frost, action of, on plant cells, 32; 
bites, 277 

Fruits, value of, as food, 22 

Fuel, for the body, 8, 14; foods, 14 

Function, of cells, 5; of cerebellum, 
203; of intestines, 64; of liver, 
56-58 ; of pancreas, 58 ; of stom- 
ach, 52 ; of red corpuscles, 73 ; of 
teeth in animals, 42 

Fur, for clothing, 178 

Gall, secreted by the liver, 56 

Gall bladder, 56 

Ganglia, 187-188 

Ganglion, 198 

Gas, suffocation from, 282 

Gases, absorbed by milk, 17 ; in 
plants, 32 

Gastric gland, 52 

Gastric juice, 5, 52-54 

Gastrocnemius muscle, 152 

Germs, destruction of, 293-294; 
in expectorations, 49 ; in milk, 19 ; 
modes of scattering, 287-288 

Glands, cells of, 3 ; lachrymal, 
218-219 ; liver, 56 ; lymphatic, 65 ; 
mucous, 47 ; of the stomach, 5, 52 ; 
oil, of the eye, 218 ; pancreas, 47 ; 
parotid, 47 ; salivary, 5, 47 ; 
sebaceous, 171-172; secreting, 
a source of heat, 180; secretory, 
39, 180; sublingual, 47; sub- 
maxillary, 47 ; sweat, 165 

Glottis, 97 

Gluten, digestion of, 53 ; in bread, 27 ; 
in cereals, 15 

Grape juice, fermented and unfer- 
mented, 35 

Grape sugar, 24, 25, 58 

Gray matter, of the cerebrum, 193 ; 
of the spinal cord, 197-198 

Growth, of body, importance of 
nitrogen to, 14 ; of cells, 3-4 

Gymnastics, 155, 157, 158 



Habit, 207; in choosing food, 

22X 229 
Habits, degrading, 202; importance 

of, helpful, 260; narcotic, 27,9; of 

health, 27)8; of imitation, 259 
Hair, the, 170-172; care of, 172; 

muscle of, 171 ; sebaceous glands 

of, 171 
Hands, care of, 172 
Head, bleeding from, 269 
Health, Boards of, 117-118; habits 

of, 258; importance of good, 1, 

154-160 
Hearing, and mental growth, 238 ; 

organ of, 233. See also Ear. 
Heart, the, 78-84 ; beating of, 

82-83, 84; cavities of, 79-80; 

contractions of, 80, 83-84, 85; 

effects of alcohol upon, 90-92 ; 

effects of tobacco, 92-93, 251; 

sounds of, 84 ; valves of, 79-80, 

82, 84, 85 ; working and resting of, 

83-84 
Heat, of body, 9, 180-186 
Heating and ventilation, 112-113 
Hemoglobin, 73 
Heredity, 208-209 
Hinge joints, 140 
Humerus, 136 
Hydrochloric acid, in the gastric 

juice, 53 
Hydrogen, 9 

Imitation, habits of, 259 ; narcotic 

habits formed by, 259 
Incisor teeth, 44, 45 
Incus, 235 

Inferior vena cava, 90 
Influenza, 290 
Injured, carrying the, 281 
Insects, in the spread of disease, 288 
Insomnia, 211-212 
Inspiration, 101-103 
Intercostal muscles, 152 
Intestine, large, 41 ; absorption 

from, 64 
Intestine, small, 41 ; absorption from, 

64 ; structure of, 62-64 
Iris, 220 

Iron, in the body, 6 
Isolation, 292-2*93 



300 



INDEX 



Jaw bones. See Maxillary 

Joints, 138-140; ball-and-socket, 

140 ; hinge, 140 ; ligaments of, 

138-139; pivot, 140; varieties 

of, 139-140 
Juices, digestive, 39, 42, 52, 58. 

£>ee also Gastric, Pancreatic, etc. 

Kidneys, 119-121; bladder of, 120; 
capsule, 119; description of, 
119-120; effects of alcohol upon, 
121 

Lachrymal, fluid, 219 ; glands, 
218-219 

Lacing, injurious to health, 179 

Lacteals, 64 

Lactic acid, in milk, 17 

Larynx, 96-98, 106-107 

Lead, poisoning from, 13 

Legs, bones of, 137-138 

Levers, use of, in the body, 147 

Ligaments, of joints, 138-139; of 
spinal column, 133 

Lime, in body, 6 ; in bones, 124 ; 
in food, 13 ; in milk, 15 ; in water, 
13 

Lime water, 16 

Linen, for clothing, 178 

Liquors, distilled, alcohol in, 37-38 ; 
harmful effects of, 38 

Liver, bile secreted by, 56-58 ; effect 
of alcohol on, 60-61 ; function of, 
56-58 ; produces heat, 180 ; sugar 
in, 58 

Lungs, air cells of, 98-99 ; and the 
blood, 71, 73, 75, 82; bleeding 
from, 269; bronchi in, 98-99; 
description of, 99-100 ; diseases 
of, 49, 270; effects of alcohol on, 
104-105 ; exercise for, 94 ; posi- 
tion of, 99 ; regulate heat of body, 
182; why air enters, 100-101 

Lymph, 65-66 ; circulation of, 66-67 ; 
corpuscles, 67 ; vessels, 64, 65 

Lymphatic glands, 65 

Malleus, 235 

Marrow, 123 

Masseter muscle, 151 

Mastication, 42 ; use of saliva in, 48 



Mastoid bone, 132 

Maxillary bones, superior, 132; in- 
ferior, 132 

Measles, 292 

Meat, as food, 15, 20, 55 ; cooking 
of, 28-29 ; effect of, on cells, 6 

Medulla oblongata, 196; functions 
of, 201-204 

Membrane, of cells, 7 ; tympanic, 
236 ; mucous, see Mucous 

Microscope, cells under, 2, 3, 6 

Milk, as a food, 15, 16-17; care of, 
17-19; constituents of, 16; curd- 
ling of, 16-17, 54; digestion of, 54 

Mind, and bodv, 201, 253; exercise 
of the, 209-210 

Mineral matter, in bones, 123 

Minerals in the bod}^, 6 ; in plants, 
21, 22, 32; in water, 12-13 

Molar teeth, 44, 45 

Mold, 33 

Mosquitoes, and the spread of 
diseases, 288 

Motion, of cells, 4-5 ; controlled 
by motor nerve fibers, 190 

Motor nerve fibers, 190 

Mouth breathing, 96 

Mucous membrane, 3 ; effects of 
alcohol on, 91-92; of alimentary 
tract, 288; of mouth, 47; of 
nose, 95, 232; of small intestine, 
62-63; of stomach, 53, 59; of 
tongue, 228 

Muscle, energy and, 9 ; proteids 
and, 15 ; tissue, 5 

Muscles, the, and animal heat, 180 ; 
contractions of, 145-147 ; control 
of, 149-150; description of, 141; 
effects of alcohol on, 150-151, 
158-160; effects of tobacco on, 
160 ; fibers of, 143 ; harmony in 
action of, 148-149 ; involuntarj^, 
143-144; names of, 151-152; 
of the hair, 171; striated,- 143; 
structure of, 142-144 ; tendons 
of, 144 ; uses of, 141 ; voluntary, 
142-143 

Myosin, 15 

Nails, 3, 172 

Narcotics. See Alcohol and Tobacco 



INl)h\\ 



301 



Nasal bones, 132 

Nasal cavities, 95 

Nearsightedness, 223 

Nerve, cells, 189-190; centers, 
200-201; current, 199; fibers, 
187-188, 190-191 ; tissue, 189 

Nerves, auditory, 233 ; cranial, 
194-196; in the teeth, 45; olfac- 
tory, 231 ; optic, 221 ; spinal, 198 

Nervous system, anatomy of, 
187-198 ; cerebro-spinal, 187 ; 
effects of alcohol on, 212-216; 
hvgiene of, 208-216 ; physiology 
of, 199-207 ; sympathetic, 187-188 

Nicotine, a poison in tobacco, 61, 
92-93 

Nitrogen, a food element, 9 ; and 
the tissues, 14 

Nitrogenous foods, 13-14, 15-22 

Non-nitrogenous foods, 14, 23-31 

Nose, bleeding from, 269-270 ; center 
of the sense of smell, 230 ; foreign 
bodies in, 275-276 

Nostrils, structure of, 230 

Nourishment, 65-66 

Nucleus, of a cell, 2 

Nurse, emergency, 283-285 

Oatmeal, as a food, 21 

Occipital bone, 132 

Occipito-frontalis muscle, 151 

(Esophagus, 41, 50 

Oil glands, of the eye, 218 ; of the 
hair, see Sebaceous 

Olfactory nerve, 231 

Optic nerve, 221 

Oxidation, 8-10, 14, 39, 180-181 

Oxygen, and animal heat, 180 ; 
and carbon dioxide, 75 ; and 
respiration, 94 ; and the blood, 
73-74 ; and the food, 9 ; supports 
life, 108-109; ventilation and, 111 

Pain,, relief of, 277-278; sensation 

of, 242-243 
Palate, soft, 49 ; hard, 49 
Pancreas, function of, 58 
Pancreatic juice, 53, 58 
Papillce, of hair, 170 ; of tongue, 226- 

227 
Parietal bones, 132 



P»tella, 138 

Pectoralis major muscle, 152 
Pelvis, 136-137 

Pepsin, 53 
Pericardium, 79 
Periosteum, 122 
Peritoneum, 41 

Perspiration, 166-168 ; checking of, 
168; conditions affecting, 167; 
object of, 167-168 

Pharynx, 49, 50 

Physiology, objects in studying, 253 

Pivot joints, 140 

Plants, and the food elements, 9 ; 
cells of, 32; how built up, 32; 
how frost affects, 32 ; poisonous, 
260 

Plasma, 71 

Pleura, 100 

Pleural cavity, 100 

Pneumonia, 270 

Poisonous plants, 280 

Poisons, antidotes for, 278-279 ; defi- 
nition of, 10 

Pores of the skin, 165-166, 173 

Portal vein, 65 

Position, importance of an erect, 
126-129 

Potash, 6, 13 

Pressure, sense of, 241-242 

Process, in cell division, 4 

Proteids, 6, 15-16 ; absorption of, 
64 ; digestion of, 53-54 ; 57, 58 

Protoplasm, 2 

Ptyalin, in saliva, 48 

Pulse, 84-85 

Pupil of the eye, 220 

Putrefaction, 33 

Pyloric opening of the stomach, 51-52 

Radius, of the forearm, 136 
Reflex action, acquired, 206-207 
and the spinal cord, 204-207 
course of nerve current in, 205-206 
importance of, 206 
Refrigerator, importance of care of, 19 
Repair of the body, 8 ; importance of 
nitrogen to, 14 ; proteids and, 15 
Respiration, 94-107 ; controlled by 
respiratory center, 202 ; restora- 
tion of, in drowning, 271-273 



302 



INDEX 



Respiratory center, 202 

Rest, importance of, 154-155, 210 

Retina, 221 

Ribs, the, 135 

Rice, and the food elements, 9 ; as 

a food, 21 
Rot, 32 

Saliva, 3, 5 ; cells in, 5, 47 ; ptyalin 
in, 48 ; uses of, 42, 46-48 

Salivary glands. See glands 

Salt, in the body and foods, 1 1 

Scapula, 136 

Scarlet fever, 291-292 

Schoolroom, ventilation of, 114 

Sclerotic, 220 

Sebaceous glands, 171-172 

Secretions, 39 

Secretory glands, 39 ; cells of, 39 ; 
produce heat, 180 

Sensation, common, 242, 243 

Senses, of hearing, 233-238; of 
sight, 217-225; of taste and 
smell, 226-232 ; of touch, tempera- 
ture, weight, pressure, common 
sensation, and pain, 239-243 

Sensory nerve fibers, 190 

Septum, of the nose, 230 

Serum, 77 

Shortsightedness, 222-223 

Sight, 217-225. See also Eyes 

Sitting, correct ways of, 127—129 

Skeleton, the, 130-140; object of, 
130 

Skin, the, 161-172; an excretory 
organ, 161 ; cells of, 5 ; coloring 
of, 164-165; diseases of, 168-170; 
effects of alcohol on, 185 ; layers 
of, 162-164; perspiration from, 
165-168; regulates body heat, 
182-183; tissues of, 161, 162 

Skull, bones of, 130 

Sleep, how to promote, 212 ; im- 
portance of, 211-212; of the 
sick, 283 

Smallpox, 292 

Smell, sense of, 230-232 ; conditions 
affecting, 230-231 ; confused with 
taste, 228 ; in animals, 232 ; loca- 
tion of, 230; use of, 231-232 

Smoking. See Tobacco 



Soda, 6, 13 

Speech. See Voice 

Spinal canal, 133 

Spinal column, 132-135 

Spinal cord, 196-198 ; nerves of, 198 ; 

white and gray matter of, 197-198 
Spinal nerves, 198 

Spitting, dangers from, 48-49, 288 
Spleen, 77 

Sprains, 139, 281-282 
Standing, importance of correct, 

126-127 
Stapes, 235 
Starch, absorption of, 64; digestion 

of, 54, 55; in cereals, 20-21, 24; 

in vegetables, 21-22, 24; sugar 

from, 24, 25, 35-36, 42, 58 
Sternum, 135 
Stings, 282 
Stomach, the, 41 ; absorption from, 

62; digestion in, 51— 56 ; juices in, 

52-54 ; movements of, 54 ; parts 

of, 51-52; position of, 51; valve 

of, 51-52 
Structure, of cells, 2 
Success, first element of, 262; second 

element of, 262 ; what constitutes, 

261 
Suffocation, from gas, 282 
Sugar, action of ferments upon, 33, 

35, 36, 37 ; digestion and, 25, 42, 

48, 58, 60 ; from starch, 24, 25, . 

35-36, 42, 58; grape, 24, 25, 58; 

in cereals, 20 ; in fruits, 22 ; in milk, 

16 ; sources and kinds of, 25-26 ; 

taste for, 26 
Summer, effects of, on system, 185 
Sunlight, importance of, to health, 

116, 284 
Sunstroke, 282 
Swallowing, 50 
Sweat glands, 165-166 
Sweeping, proper method of, 116 
Sympathetic nervous system, 187—188 
Synovial fluid, 138 

Tactile bodies, 165 

Taste, 226-230; buds, 227-228; 

sense of, 226-229 ; tobacco blunts, 

229-301 
Tea, effect of, on cells, 6 



INDEX 



303 



Tears, 219 

Teeth, care of, 46; decay of, 46; 

in animals, 1- 13 : in man, 43-46 ; 

structure of, 44-46 
Temperature, effects of alcohol on, 

L85-186; of the body, 181-186; 

of the room in sickness, 285; 

sense of, 240-241 
Temporal bone, 132 
Tendons, 144-145 
Thoracic cavity, 99, 101, 135 
Thoracic duct, 66-67 
Thorax, or chest, 135. See Chest 
Throat, foreign bodies in, 276 
Tibia. 137 
Tissue, adipose, 162 ; muscle, 5 ; 

wasting of, 3 
Tissues, food and, 14; nerve, 189; 

of the bodv, 6 ; of the bones. 

122-123 
Tobacco, effects of, on digestion, 61 ; 
^ on heart and circulation, 92-93; 

on muscles, 160; on respiration, 

105 
Tongue, a muscle, 152 ; and taste, 

226 : papilla? of, 226 
Tonsils, 49-50 
Touch, sense of, 239-240 
Toxins, 289 

Trachea, or windpipe, 98 
Triceps muscle, 152 
^tuberculosis, 290 
Turbinated bones, 230 
Tympanic membrane, 234 
Tvmpanum, 234-235 
Typhoid fever, 13, 291 

Ulna, 136 

Urea, 120-121 
Uvula, 49 

Vaccination, 292 

Valves, of the heart, 79-80, 82, 84, 
85 ; of the stomach, 51-52 ; of the 
thoracic duct, 66 ; of the veins, 89 

Vaso-motor center, 202-204 

Vegetable foods, 9, 10, 13-14; di- 
gestion of, 54 

Veins, bleeding from, 267; of the 
circulatory system, 74, 81-82; 
portal, 65 ; valves of, 89 



Vena cava, inferior, 90 
Venous blood. See Blood 
Ventilation, 108-118; heating and, 

112; of sleeping rooms, 113-114; 

of the cellar, 114-115; of the 

schoolroom, 114 
Ventricles, of the heart, 80 
Vermiform appendix, 41 
Vertebra?, of spinal column, 132-135 
Vibrations, and hearing, 235-236 
Villi, in the small intestine, 63-64 
Vocal cords, 97 
Voice, construction of, 106-107 ; 

value of a pleasing, 107 

Walking, as exercise, 156 

Waste, from the intestines, 69-70 ; 
of bodv material. 3, 8, 39 ; of 
food, 30-31 

Water, absorption of, 65 ; care in 
drinking, 55 ; gives elasticity, 12 ; 
in eggs, 19 ; in liquors, 36 ; in 
milk, 16; in plants, 32; in vege- 
tables, 22 ; purity of, 13 ; sources 
of, 12 

Weight, sense of, 241 

Wheat, and the food elements, 9 ; 
as a food, 21 

Whisky, alcohol in, 36, 38 

White matter of the cerebrum, 193 ; 
of the spinal cord, 197-198 

Whooping cough, 292 

Windpipe, or trachea, 50, 98 

Wine, alcohol in. 35 ; effects of, 35 ; 
fermented and unfermented, 35 

Winter, effect of, on system, 184-185 

Wisdom teeth, 45 

Wool, for clothing, 178, 179 

Work, habit of, 262; importance to 
success, 262; of muscles, 154-155 

Worry, dangers of, 211 

Wounds, treatment of, 265-270 

Yeast, a minute plant, 26, 32 ; 
baker's and brewer's, 33 ; in 
beer, 36 ; in cider, 33-35 ; in 
wine, 35 ; rapid growth of, 34 ; 
wild, 33 

Yellow fever, spread by mosquitoes, 
288 



MAB 2 



If 



! 



■I 




LIBRARY OF CONGRESS 




005 524 228 8 A 



































































'"•■ , ■•'■'•• "' ' ''!'. '. ' 



































;: • • :.; 





